Contra Costa County CA Archives History - Books .....Geology 1882
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Book Title: History Of Contra Costa County, California

GEOLOGY AND MINERALOGY.—There is perhaps no subject in the whole range of
scientific research so fraught with interest and so sure to yield a rich harvest
to the investigator as the study of the earth's crust, its formations and
upbuilding. In this the careful student and close observer sees more to prove
the assertion that "in the beginning God created the heavens and the earth,"
than can be found on any written page. Indeed, it may well be called a written
page—a tablet of stone on which the finger of God has written, in letters of
life and death, the history of the world from the time when the earth was
"without form and void," until the present day. What a wonderful scroll is it
which, to him who comprehends, unfolds the story of the ages long since buried
in the deep and forgotten past! In wonder and amazement he reads the opening
chapters, which reveal to his astonished gaze the formation of the igneous
bed-rock or foundation crust on which, and of which, all the superstructure must
be built. The formless and void matter is slowly crystallizing into that
peculiarly organized tripartite mass known now as granite, than which there is
no more curiously formed thing on earth, and none could be better adapted for
foundation purposes than this adamantine stone. Silica, spar and mica, three
independent substances, all crystallizing freely and separately, each after the
manner and under the laws which govern its special formation, are so
indissolubly united in one mass, that the action of the elements for centuries
is scarcely perceptible, and the corrosive tooth of time makes but a print upon
its polished surface during ages.

   From this page we turn to the one above it, for be it known that the
geological book is arranged so that its primary pages come at the bottom. Here
is found incipient life, in the form of trilobites, polyps, various classes of
mollusks, together with worms and crustaceans. Near the close of the page there
is found the record of fish also. All through the page is found descriptions of
the primal vegetable life which existed on the earth in the shape of sea-weed
and algae. The entire face of the earth was then covered with water, for this
was before the decree had gone forth which said, "Let the waters under the
heavens be gathered together into one place, and let the dry land appear." What
an era of storms and tempests that must have been! No continents nor even
islands against which the angry waves could dash in their mad fury. What tides
there must have been! But all this great commotion was necessary, for enough of
the great granite body had to be dissolved and eroded to form a body of matter
several hundred feet in thickness in the lowest places.

   Another page is turned to view, and here is to be read the fact that the sea
was full to overflowing with fish. And now the dry land had appeared, "and the
earth brought forth grass." Here was the beginning of vegetable life in the
world, other than which grew in the sea. Animal life has now advanced to the
vertebrates, and vegetable life has been ushered into the world. Great
earthquakes now begin to occur, and mountain ranges are formed. Storm and
tempest range much as in the last age, and erosion is going on rapidly, and
detritus is forming layer after layer of the rocks now classified as belonging
to this geological period. What cycles of time, as measured by man's chronology,
transpired during this age, no one can tell, yet to man, if it could be told to
him, it would seem to be not a time, but an eternity.

   The unfolding of the next page reveals to man the most useful as well as
wonderful epoch in the upbuilding of the earth's superstructure. It is now that
the great coal fields are formed, from which man, in the due fullness of time,
is permitted to draw his supplies for fuel for all purposes-How wonderfully is
the munificence and wisdom of God exemplified in this one age in the world's
formation! Quite large areas of land have now been elevated above the surface of
the raging Devonian sea. The native heat of the earth radiating continuously,
expanded the water into vast volumes of mist, which floated upward till it came
in contact with the cooler stratas of air, when it was precipitated to the earth
in grand old thunder showers. The atmosphere was charged with heat, and burdened
with moisture and carbonic acid. These were conditions most favorable for the
development of a gigantic and profuse growth of vegetation, and the> surface of
the earth was covered with such a forest as the mind of man cannot conceive.
Centuries rolled by, and at last large masses of these trees had grown up,
fallen down and formed themselves into interminable and impenetrable jungles.
Then the continents began to exchange places with the seas, and water covered
the great forests so lately in the full flush of their exotic pride. Then the
silt and sand formed great bodies of shales and slate-stone upon the top of the
forest, and the weight of the body of rock and earth pressed it till it formed
into the mass we now find it, and the process of solidification occurred, and
stone coal was the result. In accordance with the laws of correlation and
conservation of forces, the great coal beds are only immense reservoirs of heat
in a latent state, only awaiting the proper conditions for development and
application to the uses and advantages of the human family. Could a man have
seen the process of coal-making going on, away back in the almost twilight of
the early dawn of the earth's existence, he would naturally have asked: To what
use can that brittle, black material ever be put? Too fragile for building
purposes, and too hard and sterile for agricultural economies, and yet evidently
designed by the All-wise Creator for some beneficent purpose. But to-day the
answer is written on every hand in letters of living light. The sunbeam, charged
with heat, comes from the bosom of that great source of light and heat, and
assimilates itself with the great body of heat and vegetation, then everywhere
so rife. Ages roll on, and that sunbeam and its brothers of that day, have long
since been forgotten. The fullness of time has now come, and a race of beings
inhabit the earth which existed only in the will and mind of the Infinite One at
the time of the upbuilding of these great coal measures. These creatures are
called men, and they are delving far down into the deep recesses of the earth.
For what are they searching amid the dark chambers and along the gloomy passages
which they have burrowed out in the bosom of the earth? We follow and find them
with pick and drill dislodging a heavy black substance, and sending it in cars
to the surface of the ground. We follow it as it passes from hand to hand. Do
you see that happy household band gathered around the cheerful hearth, while
without the storm-king rages with all the fury of a demon? Hark! Do you hear the
clank and whir of machinery which comes from those buildings, affording
employment for hundreds of needy men and women, keeping the wolf from the door,
and even making them happy? Do you see that train of cars speeding over hill,
through valley and across plain, bearing with it a host of people, hurrying to
and from their avocations of life? Do you see the mighty steamer which plows the
ocean's crested main from port to port, from land to land, bearing the wonderful
burdens of commerce in its capacious maw? Yes, you see them all. You hear the
pulse and throb of the mighty engine which drives all these wonders on to
success, and which is so conducive to man's happiness and best good. But, did
you ever pause to think that, ere time was, almost, the agent which was destined
to perform all these marvels was garnered away in God's great store-houses—the
coal fields, and that to-day we are reaping the full fruition of all these
centuries. How grand the theme! How the heart should echo in His praise for His
wonderful goodness to the generations of men!

   The next page upwards reveals to us the fact that reptiles, frogs and birds
came into existence, or rather, that the two former developed into the full
vigor of their generation, while the latter was introduced for the first time
upon the scene of action. It is not our purpose here to make any close inquiries
into the origin of animal life, and shall use the word developed in relation to
the introduction of a new series of animal life, as being eminently proper, but
not as having any reference to the Darwinian idea of development, although the
day has already dawned when the human race will accept the truths of that
theory, let them be ever so contradictory to what is now taught. For our purpose
one theory is as good as another. The fact is that in the carboniferous or coal
period, there are no traces of birds at all; and in the next age we find their
foot-prints on the sandstone formations. Whence they came we know not nor do we
care. They were of gigantic stature evidently, for their tracks often measured
eighteen inches long, and their stride ranged from three to five feet! Another
phase of animal life was developed in this age, and that was the mammal, which
was an insect eating marsupial.

   Another page is laid open for our perusal, and on it we read that the race of
reptiles reached their culmination in this age, holding undisputed sway over
land and sea, and in the air. They were very numerous, and their forms
exceedingly varied and strange, and their size in many cases gigantic. Some
kinds, like the pliosaurus, plesiosaurus, and ichthyosaurus, were sea saurians,
from ten to forty feet in length; others were more like lizards and crocodiles;
others, like the megalosaurus and igiranodon, were dinosaurs from thirty to
sixty feet in length; others, like the pterodactyl us, were flying saurians, and
others turtles. The megalosaurus was a land saurian, and was carnivorous. This
is the first land animal of which there is any record, which subsisted on the
flesh of other animals. The pterodactyl was one of the most wonderful animals
which ever existed on the face of the earth. It had a body like a mammal, wings
like a bat, and the jaws and teeth of a crocodile. It was only about one foot long.

   The next page does not reveal any very marked changes from the last. The same
gigantic reptiles are in existence, but on the wane, and finally become extinct
during this era. The vertebrates make a great stride forward towards their
present condition, while all the leading order of fishes are developed just as
they exist to-day. Up to this time the fish had not been of the bony kind, but
now that peculiarity is developed.

   We have now perused the great book of Nature until we have come up to those
pages, which are everywhere present on the surface of the earth. Figuratively,
we may consider this page divided into three sections; the first or lower of
which contains nothing in common with the present age, all life of that day
having long since become extinct. The second section contains fossils more
nearly related to the present time, from ten to forty per cent, being identical
with the living species. In the third section the percentage of similar species
runs from fifty to ninety. The continents of the world had assumed very nearly
the same shape and outline which they maintain at the present time. Sharks
reached the height of their glory in this age, while the reptiles assumed their
true form of snakes, crocodiles and turtles. For the first time in the history
of the world is there any record of snakes, and how far they preceded man will
remain for the reader to determine from what follows further on. Birds were the
same as at the present time, so far as they went. The mammals of this age are
the chief objects of interest, not only on account of their great number and the
extended variety of forms under which they appear, but especially because this
period marks the time of the introduction of the true mammals on the earth. The
sea and estuaries, though rich in animal life, no longer furnish the most
prominent representatives of the animal kingdom; but in this period the mammals
assume the first rank. But it must be here stated that some of these species
lived beyond the close of this age. These animals inhabited the upper Missouri
section in great quantities, and comprised the moose, rhinoceros, a species
similar to the horse, tapir, peccary, camel, deer, hyena, dog, panther, beaver,
porcupine, musk deer, deer, mastodon, wolf and fox. How like a dream it seems
that these precursors of the present races of mammals should all be swept out of
existence; still, when we come to know what climatic changes occurred at the
close of this period we will not wonder any longer. Not only were the "fountains
of the great deep broken up and the rains descended," but the continent sank
deep below its present surface, and a great sea of ice from the north swept over
its face, bearing death and destruction to all living creatures in its path.
This was the glacial period, and its results are written on the next page.

   This page reveals a wonderful mystery! The throes of death were the travails
of birth, and that condition of things which swept from the face of the earth an
entire animal kingdom, paved the way for the existence of a higher and fuller
life, even man himself. Hitherto the earth had been in a process of incubation,
as it were—"the spirit of the Lord had brooded over the earth," and this was the
finality to it all. This was the long winter of death which preceded the spring
of life. This is known as the drift or boulder period, and its phenomena are
spread out before us over North America. The drift consists of materials derived
from all the previous formations, and comprise all stages from the finest sand
to boulders and fragments of rock of gigantic size. When the vast sea of ice
came crushing down from the far away home of old Boreas an inestimable quantity
of rock was caught in its giant clutch and ground to powder. Others were rolled
and polished till they were as smooth as glass, while others were fastened into
the body of ice, and carried along miles and leagues from their native ledges.
Throughout the Mississippi valley are numerous granite boulders, but no known
ledge of it exists nearer than the northern lakes. As soon as the continents had
risen from their depressed condition and the icy era had subsided, wonderful to
relate, life sprang into existence in a fuller and stronger condition than ever
before. The vegetable and animal life of this age was the same as to-day, except
the mammals, which, strange to say, passed away almost entirely at the end of
that era. The elephant during that period was about one-third larger than the
present species, and near the close of the last century one of these monster
animals was found imbedded in the ice on the coast of Siberia in such a state of
preservation that the dogs ate its flesh. Among the many pictures which this
fertile subject calls up none is more curious than that presented by the cavern
deposits of this era. We may close our survey of this period with the
exploration of one of these strange repositories; and may select Kent's Hole at
Torquay, Devonshire, England, so carefully excavated and illuminated with the
magnesium light of scientific inquiry by Mr. Pengelly and a committee of the
British Association. In this cave there are a series of deposits in which there
are bones and other evidences of its habitation both by animals and men. The
lowest stratum is comprised of a mass of broken and rounded stones, with hard
red clay in the interstices. In this mass are numerous bones, all of the cave
bear. The next stratum is composed of stalagmites, and is three feet in
thickness, and also contains the bones of this bear. The existence of man is
inferred at this time from the presence of a single flint-flake and a single
flint chip. Water seems to have now flooded the cave, and the next stratum is
composed of stones, clay and debris, such as would naturally be deposited by
water. But the strangest part of it is, that this flood stratum is rich in
relics of its former inhabitants, yielding large quantities of teeth and bones
of the elephant, rhinoceros, horse, hyena, cave bear, reindeer and Irish elk.
With these were found weapons of chipped flint, and harpoons, needles and
bodkins of bone, precisely similar to those of the North American Indians. This
stratum is four feet in thickness, and in one spot near the top there is a layer
of charcoal and burnt wood, with remains which go to show that human beings had
been there, and prepared their food by cooking it, and it also proves that the
knowledge and use of fire was known far down into the early dawn of man's
existence on earth. It is to be borne in mind that this is all anterior to the
present state of affairs, and that all the animals mentioned as contemporaneous
with these primitive men have long since passed out of existence, and may not
the race of men to which those people belonged have passed away also, and
another race sprung up in their stead, the same as other races of animals have
developed to supply the place of those passed away! These are questions worthy
more then a hasty glance. Another layer of stalagmite now appears to have been
formed, in which are bones, having the same characteristics as those mentioned
above, only the jaw-bone of a man with the teeth in it was found. Now a
wonderful change occurs. The next stratum is black mould, and is from three to
ten inches thick, but in it are found only evidences of modern times, both in
the relics of man and beast. The bones of the animals are of the orders which
exist at the present time, and the relics of men extend from the old Briton
tribes before the Roman invasion up to the porter bottles, and dropped
half-pence of yesterday's visitors. How long a time transpired between the last
visit of the first race of men who knew this cavern, and the first visit of the
old Britons is hard to even guess. That it was many ages none will dare to
question.

   We now come to the last page of the great geological book which records the
present era of the world's history, which is pre-eminently the age of man. That
man existed previous to the present order of things, there can be no question,
but it remained for this period to fully develop him in all his glories and
powers. The dark night of winter with its snows and ice, before whose
destructive and frigid breath all things which had lived on the earth had
perished, including primitive man, had passed away, and the whole face of the
earth was smiling and rejoicing in the spring-time of its new existence. The
seasons were fully established, and summer's suns and winter's ice assumed their
appropriate offices in the grand economy of the earth. The seed time of spring
and the harvest time of autumn followed each other through the cycles of
centuries with never a change. The earth was all virgin soil and very rich and
productive. The air was fresh, bracing, and free from all poisonous exhalations.
All nature was complete. Animal life had again covered the world, and all was
ready for the crowning effort .of Nature—man. Far away in Western Asia there was
a land favored far above all the countries of the earth; so much so, that it
could truly be called a paradise. It was a table-land, at the head waters of the
rivers that flow into the Euxine and Caspian seas, and the Persian gulf. Its
climate was healthful and bracing, with enough of variety to secure vigor, and
not so inclement as to exact any artificial provision for clothing or shelter.
Its flora afforded an abundance of edible fruits to sustain life and was rich in
all the more beautiful forms of plant life, while its clear streams, alluvial
soil, and undulating surface, afforded a variety of beautiful scenery, and all
that would go to make up the sine qua non of human existence. It was not
infested with the more powerful and predaceous quadrupeds, and the animals which
did inhabit the region had nothing to fear, for man was originally purely
vegetarian in his diet, and in this paradise he found ample supplies of
wholesome food. His requirements for shelter were met by weaving bowers of the
overhanging trees. The streams furnished gold for ornament, shells for vessels,
and agate for his few and simple cutting instruments. Such was man's estate in
the first days of his existence; but the eternal laws of progression soon forced
him out of his primitive bowers into huts, and thence into houses and palaces,
and the end of that progression is not yet. And the human race has a future
before which, if it could be seen and comprehended at one glance, would cause
the heart of man to stand still in wonder and amazement.

   We will now pass to a consideration of the geological formation of Contra
Costa County, as is to be found in Professor Whitney's Geological Survey of
California.

   Contra Costa Hills.—The subordinate group of elevations lying west of
Martinez and the San Ramon and Livermore valleys, is known as the Contra Costa
Hills; they extend through the county of that name into Alameda and Santa Clara
Counties, and finally become merged in the Mount Hamilton Division of the Monte
Diablo Range. These hills are separated from the principal mountain mass of
Monte Diablo by a system of valleys extending for about forty-five miles, and
preserve a somewhat distinctive character for some fifteen miles farther, losing
their identity entirely about the head of Calaveras valley. They are made up of
tertiary and cretaceous strata, usually but little metamorphosed, although a
belt extending along their western side is considerably altered from its
original character.

   Beginning at the northwest extremity of the group, at Martinez, we have in
the immediate vicinity of that place cretaceous strata, well exposed in the
bluffs along the Straits of Carquinez. Here the rocks observed are sandstones,
shales, and argillaceous limestones, the latter forming bands and lenticular
masses in the shales, generally but a few inches thick, although sometimes as
much as three feet. Their strike is usually about N. 42° W., varying, however,
from N. 39° W. to N. 44° W., and they dip southwest at an angle of from 35° to 60°.

   The rocks near Martinez have furnished a large number of species of
cretaceous fossils of both divisions.

   In passing along the shore of the Straits of Carquinez, west of Martinez, the
cretaceous strata occur for about seven miles, and are made up of shales and
sandstones, the former containing frequent thin layers of hydraulic limestone.
These rocks, however, exhibit but few fossils. The dip and strike are variable,
but generally about east and west magnetic, and the dip is also irregular, but
almost always to the southwest, and at almost every angle from nearly horizontal
to vertical; the strike is nearly parallel with the line of the Straits. Near
the upper limit of the cretaceous, are sandstones very like those of Monte
Diablo which accompany the coal, and they contain a considerable quantity of
carbonaceous matter, but no regular coal-bed, so far as yet discovered. Near
these carbonaceous strata, and above them, is a narrow belt, partly altered and
folded, and from one hundred and fifty to two hundred feet in width. The Rodeo
valley marks the limit of the cretaceous, going west from Martinez, the tertiary
succeeding in that direction, and resting conformably on the strata beneath, and
having the same general southwestern dip. South of Martinez the cretaceous
strata have a higher dip, but in the same direction.

   Southwest of the Rodeo valley lies a broad belt of tertiary rocks, which
extends from San Pablo bay to Amador valley, forming the mass of the Contra
Costa hills, for a distance of about thirty-five miles northwest and southeast,
and having a breadth of from six to eight miles. The rocks are chiefly
sandstones, and in places highly fossiliferous. San Pablo creek heads in this
belt, and flows between two parallel ridges, in the line of the strike of the
rocks. On the west side of the creek, about four miles a little south of east
from San Pablo, the rocks contain considerable bituminous matter, and a well had
been bored here in 1862 to the depth of eighty-seven feet, at which point oil
was struck, which it was proposed to purify by distillation, and works were
erected for this purpose, as also to obtain oil from the highly saturated
sandstone.* At these springs the rock has a high dip northeast; but farther
northwest it dips to the southwest, while the hills in the vicinity are too
deeply covered by soil and decomposed rock to admit of the general position of
the strata being determined satisfactorily.

    *The quantity of oil obtained seems to have been too small to pay, as the
work was not profitable, and had been discontinued previous to the oil
excitement of 1865; whether resumed between that time and the present, 1882, we
have been unable to discover.

   To the north of San Pablo are low hills of very recent strata, which are
nearly horizontal and which rest uncomformably on the edges of the Tertiary.
Whether these beds contain any extinct species of shells has not yet been
determined; at all events, they are no older than the Post Pliocene.

   In the valleys between San Pablo and Walnut creeks, many sections made by the
rains of 1861-62 in the superficial detritus are observed. The beds are
horizontally stratified, and made up of light and darker-colored materials, the
lighter ones being darker near their upper surfaces, and growing lighter
downwards to the depth of from six to twelve inches, as beds usually do when
acquiring a color from decaying vegetable substances. This would indicate that
the rate of deposition of this detritus has been exceedingly irregular, long
periods having sometimes elapsed without much addition to the detrital deposits,
and then, again, a heavy mass of materials being suddenly spread over the surf
ace, just as takes place at present during a Winter of extraordinary storms,
like those of 1861-62. The appearances indicate sometimes a heavy deposit during
one year only; at others, a succession of them for several years. The same or
similar facts are observed at many points in the Coast Ranges.

   The whole range under consideration is denuded into a great number of hills
and valleys, the latter running parallel with the strike of the strata. The
valleys are excavated in the softer materials, and are frequently drained by
streams running in two opposite directions, which connect at their sources by
very low divides, so that one hardly recognizes the fact that he is passing over
them. When streams cut across the strike of the strata, as they occasionally do,
the valleys become mere canons, or narrow rocky defiles.

   To the southeast of Martinez there is a good exhibition of the folding of the
strata exhibiting in synclinal axis, which runs from a point one mile north of
Pacheco, southwest to the Canada del Hambre, a distance of about four miles.

   "Walnut creek (Arroyo de las Nueces) heads in the divide between the valley
of this name and that of the San Ramon; it separates the Contra Costa hills from
the Monte Diablo group proper. High hills of Tertiary sandstone rise to the west
of it, attaining an altitude of from eighteen hundred to two thousand feet. The
high group of hills north of the head of the San Ramon is also of sandstone, and
has about the same elevation. The strike of the strata here is about N. 50° W.
to N. 55° W., and the dip 65°, to the southwest. The San Ramon, heading in this
group of hills, runs southeast, then turns and runs parallel with its former
course in the opposite direction, having a high and steep range of fossiliferous
sandstones between the two parallel portions.

   The foot-hills along the eastern base of these higher ridges are of strata
very much broken, with every possible dip and strike, the latter frequently at
right angles to that of the strata in the main ridge, and standing vertical.
There are indications of a line of quite recent disturbances of the rocks
through the San Ramon and El Hambre creeks, which line crosses the general
direction of the stratification at an angle of 35°. There are fissures in the
soil along the west side of the San Ramon valley, which were formed .during the
earthquake of June, 1861, and which may be considered as strengthening the
probability of the recent formation of this valley. That extensive disturbances
have taken place in the Monte Diablo chain within the most recent geological
epoch will be seen farther on.

   Near the head- waters of the San Ramon, the hills of Tertiary sandstone rise
to the height of about two thousand feet; the strata having a strike of about N.
39° to 41° W. and they have a high dip to the southwest. The same strata, as
followed along a few miles farther to the northwest, near Moraga valley, become
more nearly vertical, and the strike curves around more to the west. The same
belt of rocks extends southeast from the head of the San Ramon, through the
range of hills west of Amador valley, and they have a lower and more uniform
northwesterly dip. These hills sink into the plain near the eastern end of the
pass leading from Haywards to Amador valley.

   Near the "Walnut Creek House," a small patch of cretaceous occurs, extending
over a few acres, from which the overlying Tertiary, forming the crown of a low
anticlinal, has been denuded.

   A belt of metamorphic rock may be traced along the western side of the Contra
Costa hills, beginning near San Pablo, thence following the west side of Wild
Cat creek, and appearing in a southeast direction along the foothills of the
range, for a distance of about thirty-five miles. It generally forms a narrow
belt, not over two miles wide, and often not half that; but in some places there
is more or less metamorphic action observable over a width of four miles. The
northwestern portion of this band of altered rock curves to the northwest, and
seems to form the isolated metamorphic hills lying near the Bay, and west of San
Pablo and islands of similar rock in the Bay, apparently connecting with the
range of high hills which run out at Point San Pedro and extend back of San Rafael.

   Near San Pablo a great variety of the results of metamorphic action may be
observed; as, for instance, in following a line extending from the house of V.
Castro back to the top of the ridge.    The original rock seems to have been a
more or less bituminous slate or shale, and patches of it have almost entirely
escaped metamorphism, while others in the immediate vicinity are very much
altered and converted even into mica slate. The dip of the strata, when it could
be made out, was to the northeast, 30° at the base of the hill, and gradually
getting higher towards the crest of the ridge, where the metamorphism is most
complete.    Here the rock is traversed by small quartz veins, and has evidently
been acted on by water containing silica in solution, as it is, to a large
extent, converted into that mixture of ferruginous, jaspery and chalcedonic
material, which is so well known as frequently containing cinnabar, that we have
become accustomed to call it the "quicksilver rock." Considerable masses of
actinolite have been found lying on the surface in this vicinity, evidently
derived from the rocks of this ridge. The specimens resemble exactly those
obtained from the very much older metamorphic rocks of New England.

   The widest and highest portion of this metamorphic belt lies near the pass
leading from Oakland to Lafayette, the summit of which is thirteen hundred and
eleven feet above high tide. About a hundred rods west of the summit metamorphic
slates stand vertical, having a close lithological resemblance to rocks
elsewhere known to belong to the cretaceous system; a short distance northwest
they have a high dip to the northeast. A sharp ridge, half a mile in a direction
N. 32° W. from the Summit House, is of hard metamorphic sandstone, of which the
strike is N. 64° W., but curving more to the south as we go southward; the dip
is to the northeast, about 70° in amount. Hand specimens of this rock have a
very Trappean look, but they appear to be of metamorphic origin.

   About one mile farther north is the highest point north of the pass; called
"Rocky Mound;" it is nineteen hundred and twenty-one feet high, forming a
rounded hill, having a distinct stratification, although very Trappean in its
appearance, and a dip to the northeast. Between this point and the ridge spoken
of in the last paragraph, there is a mass of Trappean rock, finely crystalline
and very hard, in which no planes of stratification can be observed. On the
northeast of San Pablo, the unaltered strata rest on these metamorphic rocks and
dip northeast.

   The ridge between Wild Cat and San Pablo creeks is made up of strata dipping
northeast from 30° to 35°, and having a strike of about N. 52° W. The north end
of this ridge is of quite unaltered strata, while the southern portion is highly
metamorphosed.

   On the east side of Carlisle creek, a metamorphic limestone occurs, in which
all traces of stratification have been obliterated, the mass of the rock being
traversed by veins of quartz, resembling semi-opal in appearance.

   South of the pass from Oakland to Lafayette, several high dome-shaped hills
rise, having an elevation of about eighteen hundred and fifty feet, made up of
highly metamorphic rock having a Trappean aspect, but stratified and dipping
northeast. Intruded in this are masses of rock which appear to be of decidedly
eruptive origin, as the metamorphic strata aie displaced in their vicinity.
Here, as in many other localities in California, it is difficult to draw the
line between eruptive and sedimentary, as both have undergone extensive
metamorphism since their formation.

   A short distance south of the pass the metamorphic strata suddenly contract
to about one and a half miles in width, an arm of unaltered sandstone and slates
extending up between two branches of the metamorphic. In this region the slates
are little metamorphosed, appearing white and easily decomposed, although much
contorted. Portions are highly silicious, but soft and fiable, and, under the
name of "Kaolin," are used to mix with clay in making pottery at San Antonio.
This belt of slates and shales may be traced southeast as far as Sunol valley,
beneath which they dip, rising again probably and appearing in a highly
metamorphic form in the mass of the Mount Hamilton group. In the places where
they are not metamorphic they have all the lithological character of the strata
known to be of Cretaceous age, which have been described as occurring near
Martinez, and which will be noticed farther on as so well developed near Monte
Diablo.

   Lying to the west of this are massive sandstones, entirely unaltered, which
as yet have furnished no fossils, but which are believed to be of Cretaceous
age. They form an elevated ridge, of which a culminating point is Redwood peak,
sixteen hundred and thirty-five feet above the level of the bay. The strike of
these sandstones at this point is about N. 69° W., but they curve more to the
south on the southeastern side of the ridge. Their usual dip is to the
northeast, but near Redwood point the strata are much broken, and three miles
southeast they sometimes stand vertically or have a very high dip to the northeast.

   Beneath this mass of sandstones, and extending to the southwest, there is a
body of coarse conglomerate, forming a series of ridges of considerable
altitude. Northeast of San Leandro it appears in the range of hills forming the
eastern boundary of the San Antonio Ranch. Ten or twelve miles farther to the
southeast it appears in Sufiol peak, which rises to an elevation of over two
thousand feet, on the southeast side of which it dips to the southwest. It
passes through the Sunol valley and becomes a portion of the great metamorphic
belt of the Mount Hamilton Range.

   Although no fossils have been found in place in the belt of slates and shales
alluded to above as exhibiting so well marked a resemblance to rocks elsewhere
determined to be of cretaceous age, yet a few boulders have been picked up which
contained shells undoubtedly of this epoch. A more careful search will hardly
fail to furnish some farther evidence on this point. One of these boulders was
found near the entrance of Sunol valley, in a locality where it is hardly
possible that it should have come from any other belt of rocks than that
indicated above.

   The metamorphic band before alluded to, as beginning near San Pablo, after
narrowing near Redwood peak, extends along the western slope of the hills,
forming the lower ridges at their base. It does not, however, form a well
defined belt parallel with the strike of the strata, nor does it appear to
represent an axis of elevation. In a section examined from San Leandro across
the summit of Monte Diablo, it was seen conformably underlying the conglomerates
and sandstones before spoken of; but farther south its relations to the adjacent
rocks become very obscure, owing to the almost entire obliteration of the lines
of stratification consequent on the increased meta-morphism of the mass. As
observed in the foot-hills of the range between San Antonio and Alameda creek,
this metamorphic belt has all the characters which are so often exhibited by the
altered cretaceous rocks. Serpentine is abundant in it in large irregular
masses, and jaspery slates like those of Monte Diablo. East of San Antonio large
patches are to be seen, having all the characters of the quicksilver bearing
rock of New Almaden and New Idria, exactly like those noticed as occurring near
San Pablo. Considerable masses of chromic iron occur in this position, one of
which was formerly worked to some extent. Stains of copper are not unfrequent,
and have led to several attempts at mining, none of which have proved
successful, or are likely to repay the labor and capital invested.

   In the neighborhood of Alameda Canyon this metamorphic belt appears to be
almost lost; but traces of chemical action, commenced and partially completed,
are exhibited in narrow streaks visible among the highly inclined and broken
strata; these, however, do not appear to connect through with the metamorphic
mass of Mount Hamilton.

   Monte Diablo Group.—Monte Diablo itself is one of the most conspicuous and
best known landmarks in California. But few persons in the State can have failed
to recognize it from some point either of the Coast Ranges or of the Sierra
Nevada. It is not its great elevation which has given it its preeminence among
the innumerable peaks of the Coast Ranges; it is just the height of Mount Bache
near New Almaden, a point hardly known by name to those who have not made a
special study of the geography of California, and it is overtopped by Mount
Hamilton, San Carlos, and some nameless peaks to which no public attention has
ever been attracted. The reason why Monte Diablo has so marked a pre-eminence
among the peaks of the Coast Ranges is, that it is, comparatively speaking,
quite isolated, especially on the northwest, north, and northeast, the
directions from which it is most likely to be seen. To the traveler passing up
Suisun bay and the Sacramento or San Joaquin rivers, it presents itself in all
its symmetry and grandeur, rising directly from the level of the sea, and easily
recognizable from a great distance by its double summit and regular conical
outline, resembling that of a volcano, which it was generally supposed to be by
the early settlers.

   If the mountain is made such a conspicuous landmark by its isolated position,
it becomes itself, in turn, a point from which a vast area of the State may be
observed and studied. Rising as it does among the Coast Ranges, there may be
traced from its summit from Mount Hamilton on the south to unnamed peaks in the
vicinity of Clear Lake on the north, and from the plains of the Sacramento and
the San Joaquin to the Pacific, east and west. The great interior valley of
California lies spread out like a map, extending as far as the eye can reach. To
the east the view seems illimitable, and it is believed that there are few, if
any, points on the earth's surface from which so extensive an area may be seen
as from Monte Diablo. This is due to the peculiar form of the Great Valley of
California and the gradual rise of the Sierra, which brings higher and higher
points to view as the distance becomes greater. The eye can range over an extent
of four hundred miles from north to south, and back to the east, or towards the
summit of the Sierra, as far as the crest of this range, the farthest northern
point visible being Lassen's Butte, and the most extreme southernsome point near
Owen's Lake probably, thus affording a range along this snow-crested line of
mountains of over three hundred miles in length. The whole area thus spread out
before the eye can hardly be less than forty thousand square miles, not much
less than that of the whole State of New York.

   In describing the geology of Monte Diablo and its surroundings, it will be
convenient to begin with the central mass of the mountain itself as a starting
point. This central mass is made up of metamorphic rocks; it is about six miles
long, and one and a half miles in width, and is surrounded on all sides by
entirely unmetamorphosed strata. It is of an irregular crescent form, the
concave side turned to the north-northeast. The material of which it is composed
is extremely variable in its lithological character; but it consists essentially
of a central portion of very hard metamorphic sandstone, containing considerable
epidote, flanked on both sides by jaspers, silicified shales and slates. The
former constitutes the north peak, the latter the main peak, or Monte Diablo
itself. The central crescent-shaped mass of altered sandstone commences on the
northeast, about a mile and a half in that direction from the north peak, sweeps
around to the south and passes with its southern limit about a quarter of a mile
north of the main peak, then bends around to the north so as to include the
precipitous spur which runs off to the northwest, lying to the east of the head
of Mitchell's creek, and to the highest point of which has been given the name
of Eagle Point; this is two thousand three hundred and ninety-three feet above
the Bay. Extending still farther to the northwest, it crosses the creek, and
forms the high north and south ridge which makes up the most northwesterly
portion of the mountain mass. The southern extremity of this ridge is named
Black Point; the northern, Pyramid Hill; the former is about eighteen hundred
feet in elevation, the other a little less. The rocks of this ridge ar«, in
part, an exceedingly dark-colored, fine-grained, crystalline material, destitute
of traces of stratification in the central portion of the mass; but which
appears to be a metamorphic sandstone, although at first sight it might be taken
for an eruptive rock. Its relations to the surrounding rocks indicate rather a
metamorphic than an eruptive origin. It would be difficult to consider this part
of the mountain as being of purely igneous origin, without including with it the
rest of the crescentic mass, which, however, we know from its connection with
the adjacent sedimentary strata, and from the fact that portions of it have
partially escaped the metamorphic action, to be made up of detrital materials
deposited from water.

   Between the north peak and the main peak, or Monte Diablo itself, along the
narrow ridge of a little more than a mile in length which connects the two
summits, the variable character of the metamorphic rock of the mountain may be
well observed. Portions of it consist of jaspery material, or silicious slate,
distinctly stratified; these have resulted from the meta-morphism of the purely
silicious strata. Here and there are patches of imperfect serpentine, formed
from the more argillaceous sandstones; while in places the rock becomes so
highly metamorphosed as to be converted into a well-characterized mica-slate in
which numerous small garnets occur, and also zircons of minute size. The north
peak has an elevation of three thousand five hundred and ninety-three feet, or
two hundred and sixty-three feet less than Monte Diablo proper. Here all traces
of stratification are lost; but by a careful examination of the rock, where it
is well exposed in all its relations to the surrounding strata, leads
irresistably to the conclusion that it is not of eruptive origin. The gap
between the two peaks is excavated in the soft, imperfect serpentine; it is
about eight hundred feet below the summit of Monte Diablo.

   One of the best points for observing the gradual passage of the argillaceous
sandstone into the hard dioritic or Trappean rock, is along the flanks of the
ridge of which Eagle Point is the culmination. The strata here may be traced in
all stages of passage, from the soft sandstone to the hardest and most
crystalline i-ock, to which in hand specimens an eruptive origin would readily
be assigned by most geologists.

   On the outside of this great central metamorphic mass, both on the north and
south, but not entirely surrounding it, are heavy accumulations of jaspery rock,
one of the most peculiar features of the mountain, and the material of which the
culminating point itself is made up. On the north side of the North Peak, these
beds are finely exposed, forming a lenticular mass about two miles long and half
a mile wide. They have a nearly east and west strike and dip to the north. They
are here, as elsewhere, of a red color, varying from a dull brick-red to a
brilliant vermilion hue. The strata are usually thin, an inch being about their
average thickness, and they are much folded together and twisted. These jaspery
strata on the north side of the North Peak do not extend around so as to pass to
the north of the Eagle Point Eidge, but may be traced in the ravines in which
Bagley creek heads, passing into the unaltered shales of undoubted Cretaceous
age, in which ammonites inoceramus and other fossils have been found, and which
are largely developed to the north of the mountain as well as to the south. On
the north side these may be traced high up into the mountain mass along the
branches of the Arroyo del Monte Diablo. No one making an examination of this
part of the mountain could doubt that these jaspers are the result of the
alteration of the Cretaceous shales.

  The rock of the summit of Monte Diablo is the same jaspery material, filled
with fine reticulations of quartz, running through it in every direction; but,
in some places, containing a large amount of epidote, which has been formed
where the shale contained originally more lime than usual. The dip of these
metamorphic strata is distinctly to the north, and the strike along the ridge
leading to the summit is nearly east and west. At many points on the south side
of the mountain near the summit, and for a thousand feet below, these masses of
contorted jaspery strata may be seen. At one locality, just two miles west of
the summit, there is, in a narrow ravine, a most beautiful exposure of this
kind. The strata of jasper are alternately brilliant red and light green,
contrasting finely with each other, and are folded together in a manner which is
rendered very attractive from the thinness and regularity of the different
layers. The strike here is, in general, about N. 54° W., and the dip to the
north from 50° to 70°. In tracing these strata to the west, they appear to give
place to other metamorphic varieties of rock, of which serpentine is the most
prominent, and we soon reach the entirely unaltered shales as on the north side
of the mountain.

   Serpentine is found, on both the north and south sides of the mountain, in
considerable quantity. The largest mass is met with on descending the North Peak
towards the north, where it forms a lenticular deposit about two miles long and
half a mile wide, lying next to the jaspery shales. It also occurs in the gap
between the two summits, and around the head of the Arroyo del Cerro, two and a
half miles west-northwest of the summit. Here as in other localities, the
serpentine is seen in every stage of passage from the argillaceous sandstone to
the perfect serpentine itself. The boundaries are very irregular in all these
localities, especially on the Arroyo del Cerro, where we come into the unaltered
shales and sandstones on going a short distance in either direction.
   The metamorphic region, thus indicated as forming the central mass of Monte
Diablo, covers about twenty square miles, and from it a great variety of rocks
might be obtained. The red and green jasperry rocks, however, are the most
characteristic forms, and having been here so unmistakably traced to their
origin as Cretaceous shales, they have been of great service in recognizing this
formation in other localities, where the facilities for tracing it out in all
its connections, and of determining its age by fossils are less than they are
found to be in this vicinity.

   This metamorphic region has been, at various times, assiduously explored for
minerals and metalliferous ores of various kinds. Gold is reported to have been
obtained in small quantities, and was at one time the object of expensive mining
research. Cinnabar occurs at several points, especially on the northeast side of
the North Peak, where quite handsome specimens have been obtained, associated
with a silicious rock in which this ore usually occurs; it is also found on the
ridge of Eagle Point. Copper ore has also been the object of much excitement in
this region, as it is frequently found in small quantities, and occasionally in
rather large masses, in the dioritic variety of the metamorphic rock. In and
about Mitchell's Canon, where this kind of rock is most developed, a
considerable number of companies were at work in 1862 and 1863; but nothing had
been discovered which could properly be called a regular vein, or worked with
profit. It is interesting to notice, however, the occurrence of these ores in a
rock of so late a geological epoch, so evidently associated as they are with the
existence of metamorphic action in this region.

   Near the northwestern extremity of the metamorphic mass, about two miles
northwest of the summit of Black Point, is the largest mass of travertine or
calcareous trefa which has been yet observed in the State. It extends north and
south for a distance of over half a mile, forming low ridges running northwest
and southeast, and having sandstone both to the north and the south. Its width
east and west is fully one thousand feet. It is almost white, much of it quite
so, made up of a very pure carbonate of lime, and possessing the
concentrically-aggregated structure so often exhibited by masses of stalagmite.
It undoubtedly owes its existence to deposition from a hot spring, which once
came to the surface at this point. This deposit has been quarried and burned for
lime.

   It may be mentioned that there are other deposits of this calcareous material
in this region. The most extensive, next to the one just noticed, is on the
other side of the San Ramon valley, where it forms a very heavy mass on the side
of the hill, about five hundred feet above the valley. Flanking the whole north
side of Monte Diablo are unaltered cretaceous strata, having everywhere a
northerly dip, and a general strike of about east and west magnetic; the dip of
the mass is irregular, in some places vertical, but usually from 45° to 35°.
These cretaceous strata consist of shales and sandstones, the former containing
frequent beds of argillaceous limestone, which are generally less than a foot in
thickness and rarely continuous for any great length. The shales are very soft
and disintegrate easily, hence they are usually found occupying valleys between
the ridges of sandstone, which latter rock resists the weather better. The
valley at the base of Monte Diablo which separates the mass of the mountain from
the hills farther north, in which are the coal mines, is occupied by these
shales, which may be traced in the beds of the two branches of the Arroyo del
Monte Diablo, which unite at the village of Clayton.

   The same shales may be observed on the south side of the mountain, especially
in the Canada leading to Curry's house, and in the ravines running up to the
south from this Canada. As on the north side, so here, quite a number of
characteristic Cretaceous fossils are found in this belt of rock, among which
are: Ammonites Newberryanus, Ammonites Batesii, Baculites Chicoensis, Fusus
Mathewsonii, Amauropsis Alveata, Dentalium Cooperii, Dentalium Stramineum, Venus
Varians, Cardium Annulatum, Eriphy la Umbonata, Pina Brewerii, Trigonia,
Evansii, Cucullcea Truncata, Pecten Operculiformis.

   These strata, as exposed in the bed of the creek in Curry's canada, have a
very irregular dip, although usually at a high angle, and to the southeast,
south, or southwest, near the mouth of the canada near Curry's, the dip is from
80° to vertical, and the strike nearly east and west magnetic.

   Next above the Cretaceous shales with argillaceous limestones intercalated,
as just noticed, comes a very thick and heavy bedded mass of sandstones which,
on the north side of the mountain, form the elevated ridge just south of and
facing the coal mines. These sandstones contain a few Cretaceous fossils, such
as Axincea, Natica and Dentalium.

   The Cretaceous strata curve around to the south as they pass to the east of
the mountain, running out into the plains of the San Joaquin in long, low, and
almost exactly parallel ridges. The counterpart of these Cretaceous sandstones
of the north side is found also on the south side of the mountain, forming an
elevated and conspicuous ridge, sweeping around parallel with the general strike
of the rocks in this vicinity, but not forming so distinct a feature of the
topography of the region as the Tertiary-ridge next south of it. Its culminating
points rise to the height of from two thousand to two thousand two hundred feet.
To one of these points or ridges where the white soft sandstone was, at the very
summit, curiously worn into cave-like hollows, is given the name of Cave Point.
This is two thousand and seventy feet in elevation. Although these sandstones,
in this vicinity, are very barren of fossils, enough are found to determine the
fact that they belong to the Cretaceous series.

   A little south of Cave Point, in the depression between that and the next
ridge south, the sandstone is worn into curious tower-like forms, commonly known
as Tower Rocks.

   Coal has been found in the Cretaceous shales noticed above as lying under the
sandstone, but the only extensive workable beds yet discovered are included in
the sandstones belonging to the upper part of the Cretaceous.

   Of the Mount Diablo coal-beds, the only workable deposits of this invaluable
material yet discovered in the State, a full account will be given in our
chapter entitled "The Mount Diablo Coal Field." Leaving this section of our
theme, therefore, we will follow the geology of the region so far as it concerns
the limits of this county.

   The exact limit of demarcation between the Cretaceous and the Tertiary, in
this vicinity, has not been exactly made out. Eesting on the coal-bearing strata
above described, there is a heavy mass of sandstone, with some shales
interstratified, which, however, are more silicious than the truly Cretaceous
beds of otherwise similar character. These beds appear to be beds of passage
between the Cretaceous and the Tertiary; but fossils are so extremely rare in
them that it is not easy to come at their precise relations. They hold the
position which should be occupied by the Eocene Tertiary; but have yielded no
forms recognized elsewhere as of this particular age. This mass of sandstones
occupies, on the north side of the mountain, a considerable width on the
surface, apparently not less than a mile to the north of Mine Hill. On the south
side it appears less distinctly marked; in fact, there seems to be but little
room for this body of strata between those of undoubted Cretaceous age at Tower
Rocks, and the high ridge of Miocene Tertiary directly south of it.

   Rocks of both Pliocene and Miocene age are extensively developed to the north
of the strata first spoken of, on the northern slope of the range in which are
the coal-mines. Those which are referred to—the Miocene division of the
Tertiary—consist chiefly of sandstones, which are very heavily bedded towards
the base of this part of the series. They are succeeded above by thinner and
more fossiliferous strata, which not only contain large numbers of marine
fossils, but also impressions of leaves and considerable fossil wood, the latter
silicified and lying upon the surface, the rock having decomposed around it.
These upper strata are referred by Mr. Gabb to the Pliocene division of the
Tertiary, from a consideration of the number of living species which they
contain, as well as from their stratigraphical position.

   Resting upon these are strata of volcanic materials, such as ashes and
pumice, which have evidently been ejected or washed into water and deposited in
a stratified condition. These beds to the west of Kirker's Pass have a thickness
of several hundred feet, and rise into considerable hills. Their dip is usually
about 25° to 30°; but in some places they are elevated at as great an angle as
50°. Their straike is also somewhat irregular, and they form a series of rounded
and bare hills, stretching along near the edge of the San Joaquin plain.

   Above the sedimentary volcanic beds just noticed are beds of gravel and loose
materials, probably a Post-Pliocene age, which also have a considerable but
variable thickness, and which pass gradually into the modern deposits of the
valley. All these strata, from the Cretaceous up to the Post-Pliocene, appear to
be perfectly conformable with each other, and they all have a northerly dip,
although it is variable in amount.

   TOPOGRAPHY.—The Sacramento river is navigable from the bay northward to
Sacramento, one hundred and twenty miles, for large, commodious steamers, as
fine as any upon the rivers in the Eastern States. They ply daily to Sacramento
northward, stopping at Martinez, New York and Antioch; smaller, light-draft
steamers ply regularly to Red Bluff, two hundred and fifty miles further, and on
the Feather river, sixty miles to Marysville. The San Joaquin river is also
navigable for large steamers, which ply daily to Stockton, one hundred and
twenty miles. Above Stockton, light-draft vessels ascend toward Visalia, two
hundred miles, and also for some distance up its branches, the Stanislaus and
Tuolumne, and also the Mokelumne river. The light-draft steamers on all these
rivers carry with them large barges, in which the crops of the farmers, firewood
and other products, are cheaply and rapidly transported to a market at San
Francisco at very low rates. A number of the creeks and sloughs emptying into
the Bay of Suisun are also navigable, and ascended by numerous steamers and
sailing craft, which carry freight and passengers at reasonable prices. Thus a
great portion of the county is, to a great extent, independent of* the railroad,
while the competition between land and water carriage insures low rates of
freights and fares on both.

   The course of the San Joaquin is very tortuous; and a writer thus describes a
trip up the river by steamboat: "Looking through the cabin windows we see the
brown banks of the river just below Antioch. By the time breakfast is over we
are nearing False river and leaving Sherman Island. We go on deck and look
around. Contra Costa lies just behind, its bare hills rising to the height of
Mount Diablo, which, looked at from this low level, towers up very grandly. The
flat extent of San Joaquin is to the right, while to the left the Montezuma
Hills show quietly over Sherman Island. The view, however changes almost every
minute as the steamer follows the channel, and Mount Diablo is as often seen
over the bow as over the quarter, whilst sometimes it seems as though we were
leaving it behind, only to find it almost instantly staring us in the face. The
banks begin to narrow in as the afternoon comes on, and when we enter the west
channel of the San Joaquin the character of the surroundings is entirely
changed. The stream is narrow and flows apace, whilst willows grow down to the
water's edge, the tule flags forming an outlying and lower fringe. Levees lie
along most of the distance, covered now with alder and dwarf poplars, while here
and there tree-covered mounds look like the farm groves of New Jersey. We are
now between Union Island and the mainland, and the character of the banks has
changed again. The pleasant green timber has gone, and the tule is everywhere.

   "The San Joaquin river has such an erratic course about here that the only
method of threading the curves and loops is by running the steamer's nose plump
into the tules on this side, which fends her off until she swings around enough
to plump her nose into that side."

   The San Joaquin river is divided into three branches, known respectively as
the West, Middle and East channels—the latter named being not only the main
stream, but the one used by the steamboats and sailing vessels bound to and from
Stockton—or, at least, within four miles of that city, from which point the
Stockton slough is used. The east or main channel is navigable for small,
stern-wheel steamboats as high as Fresno City.

   The first mail ever carried up the Sacramento river was on the 24th of July,
1849, by Captain Seth M. Swain, of Martinez, in the schooner "John Dunlap." The
mail matter was all contained in one bag, and the Captain received six hundred
dollars for the service, while the entire postage on the contents of the mail
was less than sixty dollars.

   Suisun Bay is one of the chief bays that border the Contra Costa coast. Many
of the gold-seekers here found a watery grave, or foundered upon the middle
grounds of the bay. Says Rev. W. W. Smith: "One schooner, in the fall of 1849,
struck on the lower end of the middle ground, and the winds and waves soon broke
her up, and the flour with which she was laden was cast into the bay. Those
coming up the bay would pick up a barrel or two for use, and one large boat was
engaged a long time in hunting up the barrels of flour, which were sold to the
baker of New York of the Pacific for five dollars per barrel. Supposing them to
be worthless, some refused to give any price; but they were but little damaged,
even after a week's soaking in the water of the bay, wetting the barrel and
flour half an inch deep, making the whole impervious to water.

   "Another schooner struck, three miles from New York, on a spot not so
dangerous, and she was strong and staunch-built, so that she sat upon the sand
of the middle ground, and the sailors could walk around her at low tide. The
captain and crew found a near cut to the channel, and by the use of the miners'
spades and the work of the passengers, they dug a passage from the schooner, and
the wind and tide serving right, they on the tide floated, and having a kedge
anchor out in the right direction, the schooner and cargo were saved, and they
all went up the bay rejoicing at their good luck and escape from the dangers of
the Suisun Bay.

   "A number of boats were swamped and stove upon the middle bars of sand in
this bay, before a perfect map of the bay was known by the hurrying crowds who
were compelled to navigate these waters to take their traps to Stockton and
Sacramento. One boat was foundered, and the men swam to the south shore across
the channel, but cold and wet they had to swim another slough one hundred feet
wide, and then came to New York Landing for aid.

   "Whale boats have stayed at New York waiting for a week at a time for the
winds to settle, and came down before venturing upon the Suisun Bay.

   "The ship Henry Lee was anchored in the harbor with short chains; the
northers caused her to drag her anchor, but the banks on the south shore were
such that she would work up and down to the south shore line in tides; and thus
she was left to care for herself for about a year—1850— without grounding. She
was taken in unharmed to the city and sent to sea. There is not a rock or shoal
for all the distance .from a mile below Antioch to Marsh's Landing, three miles
above the town; making four miles in length, and wide enough for four or five
ships to lie side by side and swing at the chain. The channel is on an average
of about forty feet deep, and the clay banks are straight up and down."

   The largest valley of Contra Costa County opens about midway of the northern
boundary on Suisun Bay, about six miles wide, east and west, and fifteen long,
north and south, reaching up to the foothills of the Mount Diablo spurs, and
comprising portions known by various names, as Pacheco, Diablo, Ygnacio, and
Walnut Creek Valleys. Other smaller but important and beautiful little
serpentine valleys coil up and almost surround the mountain, till lost in the
narrowness of their waterways. The most important of these small valleys is San
Ramon, extending from Walnut Creek Valley south, to the Alameda county line,
quite dividing the main range of mountains from its Diablo spur, making a
natural and easy highway through the county and around the peak of Diablo. In
places this valley is as narrow as half a mile, while at others it spreads to
one and a half miles, with three villages and dozens of highly prized farms and
homes in a length of ten miles. The other only important valley in size is the
San Joaquin, having a length of twenty-seven miles in the county by three and a
half in breadth—reaching from the great central valley described at a spur of
Diablo, called Bay Point, along the San Joaquin River east to the county line,
and at a right angle with the other valleys mentioned. These valleys have a
gentle descent to the bay and river on the north. Three busy villages occupy the
water front of the San Joaquin Valley, and two others the foothill slopes and
lower canons. The foothill villages engage in raising the stores of fuel for
improvident man, that an All-wise Creator laid up for him; the three coast towns
engage in a mixed commerce of coal and food staples grown in the valley about.

   The Alhambra Valley, west of the central or great Diablo Valley, and only
divided by three miles of rolling hills, opening on the Straits of Carquinez, is
narrow and but a few miles in length, but fertile and picturesque in its fringes
of evergreen oaks, and dots of cottages white, and life in toiling, happy man,
and useful beast. It has the county seat nestled upon its water line. Moraga, an
elevated valley, in the west, with Taylor, Rodeo, Briones, Pinole and San Pablo,
all small valleys among the hills of the western part of the county, go to make
up the smiling dimples in the face of our mountainous county. No lakes or rivers
add variety to the landscape, we regret to say, and few streams of any size
endure throughout the usual season of drought, from April to November.

   The Diablo meridian line divides the county most completely in three ways—in
longitude, or as we express it in government surveys, as range east and west—in
temperature and rain-fall, and in the difference in territory claimed under
Mexican grants. From this north and south line west, nearly the entire half is
comprised in Mexican grants, there being twelve grants ranging from
three-fourths of one to five leagues in extent, while east of the meridian there
are only three. We do not reckon the Western Pacific Railroad concession, which
ranges along the southern border, and spreads its uncertain shadow of twenty
miles wide over half of the country from west to east.

   The one hundred and ten miles of tule delta, in the northern corner of the
county, is estimated to approximate one-sixth of that kind of land in the State.
It is slowly increasing from natural causes. Much time, labor and capital have
been expended in trying to successfully reclaim it from its annual overflow of
tide and river, and appropriate it to agricultural and grazing purposes, with
but small measure of success as yet. This portion of the county properly belongs
to the San Joaquin Valley, but is a distinct feature in the county, and the
contrast from such elevated vales as Moraga in the west, is a novel peculiarity.
One has a valley elevation of about seven hundred feet over several miles, while
the other, over a larger space, bathes itself twice daily in the restless tide
of Suisun Bay.



Additional Comments:
Extracted from:

HISTORY OF CONTRA COSTA COUNTY,
CALIFORNIA,
INCLUDING ITS GEOGRAPHY, GEOLOGY, TOPOGRAPHY, CLIMATOGRAPHY AND DESCRIPTION;
TOGETHER WITH A RECORD OF THE MEXICAN GRANTS; THE BEAR FLAG WAR; THE MOUNT
DIABLO COAL FIELDS; THE EARLY HISTORY AND SETTLEMENT, COMPILED FROM THE MOST
AUTHENTIC SOURCES; THE NAMES OF ORIGINAL SPANISH AND MEXICAN PIONEERS; FULL
LEGISLATIVE HISTORY OF THE COUNTY; SEPARATE HISTORY OF EACH TOWNSHIP, SHOWING
THE ADVANCE IN POPULATION AND AGRICULTURE;
ALSO,
Incidents of Pioneer Life; and Biographical Sketches
OF EARLY AND PROMINENT SETTLERS AND REPRESENTATIVE MEN;
AMD OF ITS TOWNS, VILLAGES, CHURCHES, SECRET SOCIETIES, ETC.
ILLUSTRATED.
SAN FRANCISCO: W. A. SLOCTUM & CO., PUBLISHERS
1882.


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