Chapter VII: Part I: , p. 1-96, for 1863, printed in April to December, 1863 (7)

By reference to the statistics below, it will be seen that even
mountain districts, where during the day there is much less of
turmoil and noise arising from business than in the populous
city, that of all those noticed, none have been of sufficient
intensity to attract the attention of the inhabitants during
the hours of daylight. These facts, though few in themselves,
are of importance, to disabuse the public mind in relation
to the danger to be apprehended from the occurrence of these
phenomena. The character which we sustain both at home and
abroad, as being in constant danger of being swallowed up
by these occurrences, and that our country is but a bed of
latent volcanoes ready to burst forth at any moment, spreading
devastation over the land, is one of the greatest fallacies
that ever obtained possession of the human brain. Our State is
as primitive as Massachusetts or New Hampshire, and the dangers
that surround us from the sources above mentioned, are equally
great as in the States just named.

We should remember that when speaking of California as a
State, that we include a line of territory equaling that of
the seaboard lying between Cape Hatteras on the south and the
British Possessions on the north, and including eleven of the
seaboard States of the Union; and when we place our comparative
estimates on this basis in matters of this character, it will
become at once evident that the danger of annihilation from the
causes under consideration, are not of that magnitude which at
first sight would appear.

Along the coast of Mexico and Central America, to the south
of California from all the records that are obtainable here
there appears to have been a much greater exemption from those
phenomena than has been usual in former years; this seems to
have been the fact, also, throughout the Pacific, Oceanic, and
most of the Continental Islands along the coast of China, while
to the north and north-west, beyond the fifty-fifth parallel,
both volcanic and earthquake phenomena appear to have been
greater than usual. This has been observable, for the most
part, in the neighborhood of the Aleutian Archipelago, along
the north-east coast of Japan, and in the British and Russian
Possessions of North America on the Pacific, and islands of the
Ochotsk Sea.

It would be interesting to know more of the predominance of
these phenomena in those regions, and such information could be
easily obtained from the commanders of the whaling fleet, if
the proper measures were adopted to secure it.

Below will be found some interesting matter upon this subject,
which took place during the past year near the Straits of
Ourinach.

The earthquakes which have occurred in this State during 1856,
and the period of their occurrence, is as follows:

January 2d, 10h. 15m.—This morning, a smart shock of an
earthquake was felt in San Francisco. The motion of the earth
was undulatory, and came apparently from the northward. A
pendulum indicated a motion of about five and a half inches.

January 21st, 16h.—Quite a smart shock occurred; it was quite
sharp in the south-west part of the city.

January 28th, 3h.—At the town of Petaluma, Sonoma County, a
shock of an earthquake occurred. It was sufficiently heavy to
awake persons from their sleep.

January 29th, 0h. 45m.—A slight shock was felt in San
Francisco. It was observed also at the Mission Dolores. There
were three distinct tremors, with short intervals elapsing
between. The motion was apparently from the westward.

February 15th, 5h. 25m.—A severe shock of an earthquake was
felt in San Francisco, the duration of which was about eight
seconds. Persons sleeping were aroused, and many persons left
their beds and sought the street. There were two distinct
shocks, the second very light and scarcely perceptible. The
motion was _undulatory_ and _vertical_, and at the end of the
first shock a very strong, profound jar, with which it ceased.

The upper part of a building on Battery Street, for seventy
feet in length, was thrown down, the whole of which was above
the cornice, very thin, and the mortar with which it was
constructed had not become hardened, being easily removed by
the fingers—it more resembled wet sand than a firm mortar.

There appears to have been but little difference in the
sensation of persons situated either in upper or basement
stories.

It was preceded by a deep, heavy rumbling, and the motion
apparently came from the north-west. A distinct shock was felt
at eight minutes past two o’clock the same morning, by persons
who were awake and up at the time.

The rotatory movement was shown in the fact that small square
bottles and boxes that stood upon a line, were moved from their
position horizontally, describing an arc of thirty degrees and
upwards, as shown by the dust upon the shelves on which they
stood.

The first wave came with a force sufficient to project small
articles three or four feet on the floor, from shelves on which
they were placed; they were apparently all thrown in the same
direction. Several clocks were stopped at precisely 5 hours 25
minutes.

All the cracks in walls and ceilings had a direction nearly
north-west and south-east, and most of them had the appearance
of having been produced at the moment of elevation.

The earthquake was felt heavily at Monterey, at five hours
twenty minutes; it was also felt at Bodega, but no time is
given.

The vessels on the coast, and ranging from San Pedro on the
south to Southern Oregon, and at distances varying from eight
to one hundred miles from land, did not experience any shock.
They were twenty-two in number.

Up to the present date the most northern point of which we have
any record of its having been felt, is at Santa Rosa, which
is fifty-three miles north of San Francisco, and at Monterey,
ninety miles south of the latter place; to the east of this
city we have no record beyond Stockton. This would give for
its length one hundred and forty-three miles, and its breadth
sixty-six miles.

Inquiry was made through the State line Telegraph at El Dorado,
Nevada, Downieville, Placerville, Marysville, Sacramento,
Stockton, and San José; it was not felt in any of the
localities named, excepting the two last, and at Stockton it
was quite light.

If the time as given at Monterey was the same as at this city
(San Francisco), the velocity of the earth-wave must have been
much slower than that of the great earthquake at Simoda.

March 24th, 22h. 20m.—A slight shock was felt at Canal Gulch,
Siskiyou County, also at Yreka. The motion is described as
being horizontal.

March 31st, 13h. 25m.—A light shock was felt in San Francisco.
It consisted of three light but distinct tremors.

April 6th, 23h. 30m.—A smart shock was felt at Los Angeles and
the Monte, people were aroused from their beds.

May 10th, 21h. 10m.—A light shock was felt in San Francisco.
The shock was accompanied by a loud report, like the discharge
of a cannon; people mistook it for the signal gun of the mail
steamer. This was felt at Monterey, and in Contra Costa County.

May 2d, 0h. 10m.—A severe shock was felt at Los Angeles. It
caused much trembling among the buildings, and considerable
alarm among the people, many leaving their beds. The shock was
preceded by two loud reports like the blasting of rock; it
apparently came from the north-west; no damage was done.

August 2d, 5h. 20m.—A light shock was felt in San Francisco.
It was sufficiently strong to awaken persons in bed; it was
evidently more severe in Stockton.

August 27th, 21h. 15m.—An earthquake was felt at Mission San
Juan, Monterey County. There were two distinct shocks with
short intervals elapsing, the second being the heaviest. The
motion is described as undulatory and coming from the west. It
was felt at Monterey and at Santa Cruz.

September 6th, 3h.—A smart shock felt at Santa Cruz. It created
considerable consternation and many persons left their beds.

September 20th, 23h. 30m.—A very severe shock was felt in
different parts of San Diego County, and at that town. At
Santa Isabel the ceilings of the dwellings were shaken down;
the cattle stampeded and ran bellowing in all directions, and
the Indians seemed equally terrified. The walls of the adobe
buildings were many of them cracked. The motion is described
as oscillatory. A light shock occurred on the following Monday
morning.

November 12th, 4h.—A smart shock occurred at Humboldt Bay.
Another shock was reported but no date given.

From the record before us it will be seen that of fifteen,
the total number of earthquakes recorded during 1856, seven
have been felt in San Francisco in common with other parts
of the State; seven have occurred south of this locality
that were not observed here, and four north of it. Of the
seven shocks noticed here five only were not observed in any
adjacent district, and may be considered as strictly local.
The periods of the year at which the shocks have occurred, are
as follows: During the winter months, five; during the autumn,
three; during the spring and summer, six. None have taken place
between the vernal and autumnal equinoxes.

We have records of considerable and violent volcanic phenomena
throughout the northern seas, and islands both to the east and
west of Alaska. The Russian frigate _Dwina_, while lying at
Shuam Shu, brings intelligence of the outburst of a volcano
in that vicinity about the twenty-second of June, and on
the twenty-fifth of the same month passed through fields of
floating pumice; the latitude by observation being fifty
degrees fifty-three minutes, and longitude one hundred and
fifty-eight degrees thirty-two minutes east, per chronometer.

An interesting account of a submarine volcano was reported by
the Captain of the bark _Alice Frazer_, in latitude fifty-four
degrees thirty-six minutes, longitude one hundred and
thirty-five degrees west, which is as follows: A portion of the
whaling fleet, four in number, were running through the Straits
of Ourinack, on the twenty-sixth of July last; while passing
the straits a submarine volcano burst out, sending a column of
water several hundred feet upward; immediately following this,
immense masses of lava were projected into the air, and the sea
for miles and for days afterward, was covered with floating
fragments of pumice. The ships _Scotland_ and _Enterprise_ were
nearer the volcano than the ships _Frazer_ and _Wm. Thomson_;
on the decks of the two former considerable pumice, lava, and
ashes fell. There were seven vessels in the straits at the time
of the occurrence, three of which names I could not learn.

The outburst was accompanied with violent shocks of earthquake.
It is the opinion of Captain Newell, of the _Alice Frazer_,
that considerable shoaling has been the result of this
submarine action.

ON THE DIRECTION AND VELOCITY OF THE EARTHQUAKE IN CALIFORNIA,
JANUARY 9, 1857—BY DR. JOHN B. TRASK.

The earthquake which occurred in various parts of this State,
on the morning of the ninth January last excited at the time
considerable attention. This arose from two causes. First,
from the varied reports that appeared on the following day
through the press of the city, detailing its occurrence in
remote mountain towns, and for which there was no foundation.
Secondly, from the great extent over which the commotion was
felt, as was subsequently proved.

Immediately following the occurrence of the phenomenon, letters
were addressed to all the principal towns between Mariposa and
Downieville, east of the valleys, for the purpose of learning
how far the shocks may have extended eastward of this city.
These letters were forwarded by the Pacific Express Company
to their agents, and through them answers were returned in
every case but two through the same source. From the facts
thus obtained, it was found that in no locality east of the
foothills, _was any shock felt on that day or night_.

Another report, equally unfounded, reached us on the arrival of
the steamer from the southern coast, to the effect that several
houses had been demolished in San Diego from its violence,
while the facts in the case are _that the steamer left that
port twenty-four hours before the shock occurred there_.

This earthquake, or more properly speaking the series of shocks
that began on the night of the eighth in this city, and which
continued in the south part of the State during the following
day and night of the ninth, was probably the most extensive of
any on record on this portion of the Pacific coast, excepting,
perhaps, that of the wave of the Simoda earthquake in December,
1854. The linear distance over which we are able to trace its
course, amounts to six hundred and two miles, and its breadth,
so far as now ascertained, is two hundred and ninety miles. It
has all the appearance of having been the terminal movement of
some more violent commotion at a distance from our coast.

From the best evidence obtainable at present, it seems to
have had its origin to the west and traveled in an easterly
direction. This is conclusively proved from the fact that it
was felt earlier at San Francisco than at any other locality
east of this city within the State. We have no record as yet of
its occurrence along the coast of Mexico or of Oregon.

I have been able to determine with considerable accuracy the
period of time at which the shock between eight and nine
o’clock on the morning of the ninth took place, at four
localities east of the City of San Francisco, in this State;
as the shock at that hour seems to have been more generally
noticed than those which either preceded or followed it here
or elsewhere, though at this city it was much less marked than
the shocks at 1h. 33m., 4h. 15m., and 7h., these three latter
occurring at those hours of the morning when most persons are
sleeping. The shock at 7h., produced a circular motion in the
pendulum, the diameter of which was about five inches. The
oscillations of the pendulum in all the others were in an
easterly and westerly direction.

The precise period of time at which the shock took place at San
Francisco, between eight and nine o’clock, is determined by
the stopping of a time-piece belonging to J. W. Tucker, whose
rate of error was three seconds fast. The time at San Diego was
furnished by Mr. Cassidy, of the army, and that of the Tejon
Reserve is by persons at that post. To private gentlemen at
Sacramento and Stockton we are indebted for the time at those
places. The accompanying table of latitudes and longitudes
of localities named, gives the hour at which the shock took
place at each; the difference or elapsed time, from which
the velocity was deduced, are the mean times corrected for
the places named, the time as given above being taken as the
standard at San Francisco.

It is proper to state that three minutes four seconds, was the
greatest error in time found, and the least was twenty-two
seconds:

--------------+-------+--------+----------+---------+----------
LOCALITY. | Lat. | Lon. | Time of | Elapsed | Velocity.
| | | shock. | Time. |
--------------+-------+--------+----------+---------+----------
| ° ´ | ° ´ | h. m. s. | m. s. | miles.
San Francisco | 37 48 | 122 25 | 8 13 30 | 0 00 | 0 0
Sacramento | 38 32 | 121 23 | 8 20 00 | 7 30 | 6 6
Stockton | 37 52 | 121 34 | 8 23 00 | 9 30 | 6 5
Tejon | 35 00 | 118 46 | 8 45 00 | 32 30 | 6 0
San Diego | 32 42 | 117 13 | 8 50 00 | 36 30 | 7 0
--------------+-------+--------+----------+---------+----------

The velocity is given in miles per minute, and by dividing the
sum of the same by their number, it will be found that the
movement of the wave at that time averages a fraction over 6.2
miles per minute.

The results obtained from the above data approximate closely
the deductions of Prof. Bache on the wave which reached our
shores and resulting from the earthquake at Simoda on the
twenty-third December, 1854, and which will be found in a
paper read by that gentleman at the meeting of the American
Association for the Advancement of Science, during the early
part of last year.

From the facts before us, there can be but little doubt of the
direction of the commotion, and that it proceeded from the
west, or a little south of that point. The motion of the earth,
as described at the different localities at which it was felt,
with the motion of the pendulum—which was slightly south of
a west line—leads to that conclusion. Time is an important
element in aiding us to form correct conclusions regarding
these phenomena, and it is to be hoped that our friends in
different parts of the State, in reporting the same, will be
precise in this particular. Of the incidents attending the
shocks, many and varied reports have reached us; it seems to
have acted with greater violence in the vicinity of the Tejon
Reserve and upper Tulare County than at any other place. It is
most remarkable that so small an amount of intensity of force
was manifested when the area over which it extended is taken
into consideration.

The effects were felt in San Francisco several hours before
they are reported to have been observed at any other place
north or south. They began here at twenty minutes past eleven,
on the night of the eighth, and continued till thirteen minutes
past eight the following morning—six shocks occurring in the
interval; while to the south, the first shock noticed at the
Tejon, was at six hours thirty minutes, on the ninth. In Los
Angeles they continued at long intervals through the day until
twenty-three hours thirty minutes of the same date. I have
learned from persons who were present in Los Angeles at this
time, and also at the shock of the fourteenth July, 1855, that
the severity of the latter exceeded that of the ninth January
last past.

1857.

During the past year there has been rather a frequency in the
occurrence of the phenomena of earthquakes; and, with the
exception of two, there have been none that were particularly
remarkable either for extent of surface affected or severity
of action. In one, that of the ninth of January, the greatest
extent of surface, and greatest intensity of action was
manifest. Its principal force seems to have been expended in
the more southerly portions of our State, and in the immediate
vicinity of those volcanic (?) vents found at different
localities upon the Colorado Desert. It is manifest, however,
that this shock and those which preceded it on the night of the
eighth, had their origin to the west of our coast, as the times
of occurrence of the shock at different localities most fully
prove. This matter was fully discussed in my previous paper,
“On the direction and velocity of the earthquake of January
9th, 1857,” read before this Society March 30th, which will be
found in their proceedings.

The other shock of greatest extent, on the second of September,
extended over an area of about two hundred miles, but was
marked by no particular severity or injury, except that of
fright to those who experienced it.

The whole number that can be authenticated as occurring during
1857, amounts to seventeen, being greater than the number
recorded in 1853 and 1856; and it would seem probable from
our records that this number is the maximum to which we shall
probably be subjected in this State.

From the Sandwich Islands we have no news of earthquakes save
one, which is here inserted: “A very severe shock of earthquake
was felt at Kawaihae, Hawaii, on the twenty-fourth of February,
the most severe that the residents there have had for many
years.”

The arrival of the whaling fleet from the Northern seas brings
no intelligence of the occurrence of these phenomena, as was
the case of the preceding year; hence, the presumption is,
that subterranean action has not been violent in those distant
regions during the year just passed.

On the coast of Mexico, and inclusive between the twenty-fifth
and thirty-second parallels, we have received intelligence of
the occurrence of one earthquake, which appears to have been
felt on both shores of the Gulf of California for a distance
of nearly two hundred miles, both north and south. We have no
records south of that point.

The shocks which we can authenticate within the limits of our
own State, are as follows:

January 9th.—This shock was felt from Sacramento to the
southern boundary of the State. It was preceded by three smart
shocks the night and morning previous. At Santa Barbara water
was thrown over the surface from a shoal well, seven feet deep,
the water in which was less than three feet in depth.

January 18th, 9h.—A light shock at Martinez and Benicia.

January 20th, 8h. 30m.—A smart shock was felt at Santa Cruz and
Mission San Juan.

January 21st, 23h.—On the evening of this day a smart shock
was felt at Mariposa. The wave and sound seemed to travel from
north-west to south-east. It was accompanied with a report like
that of a distant gun.

February 5th, 7h.—A smart shock was felt in San Francisco,
which shook the buildings that are situated on made-ground very
severely, while those situated on firmer bottoms were affected.
This shock was felt at Oakland and Stockton, but was not felt
at San José or Sacramento, as reported at the time.

March 14th, 15h.—A severe shock was felt at Santa Barbara and
Montecito. It was momentary in duration, attended with a loud
report.

March 23d, 12h. 27m.—A light shock in San Francisco.

May 3d, 22h.—A smart shock at Los Angeles and the Monte.

May 23d.—A light shock at Los Angeles; a report also that a
severe shock had been felt at Fort Tejon.

June 14th.—A shock was felt at Humboldt Bay. On the same day
several severe shocks were experienced at the Penal Island
(Carmen), Gulf of California, and which extended almost ninety
miles north and south of the island.

August 8th, 11h.—A smart shock was felt at Rabbit Creek, Sierra
County.

August 29.—A severe shock at the Tejon Reserve. No time is
given.

September 2d, 19h. 45m.—A light shock at San Francisco. This
shock was felt at Sacramento, Marysville, Nevada, San Juan,
Downieville, and Camptonville.

September 14th, 2 P.M.—A light shock in San Francisco.

October 19th, 18h. 30m.—A severe shock of an earthquake in San
Francisco.

October 20th, 12h. 8m., 12h. 35m., and 13h. 15m.—Three other
shocks occurred; the last was equally severe with that of
January 9th, at 8 A.M. People were much frightened, and left
their beds. The shock was felt at San José, but not at Oakland.

November 8th, 8h. 45m.—A shock at San Francisco, which was felt
at Oakland and Bodega. December 23d, 7h.—A light shock at San
Francisco.

Of the whole number which have occurred during the year, two
only have been felt at San Francisco that were not experienced
at other localities, and four others have occurred which have
been felt in common at other portions of the State—thus making
about one-third of the whole number that were in common here
and elsewhere.

Eight of the aggregate have occurred between the summer and
winter solstices.

Seven have occurred during the spring and summer months, and
ten during the winter and autumn.

Eight have occurred between the vernal and autumnal equinoxes.

1858.

During the past year we have had occasion to note the
occurrence of eight shocks of earthquake in this State. This
number is one-half less than that in 1857, and one-third less
the number in 1856. The shocks, with one exception, have been
unmarked by anything like violence, being little else than mere
vibrations or tremors, not noticeable by the great majority of
the people. They are as follows:

February 10th.—A smart shock at Kanaka Flat, Sierra County. No
time noted.

February 15th, 4h. 20m.—A light shock in San Francisco. Was
observed in the County of San Mateo ten miles south of the city.

August 19th, 22h. 10m.—A light shock in San Francisco. The
motion was east to west, and was undulatory.

September 2d.—A smart shock at Santa Barbara, no time given.

September 3d, 0h. 40m.—A smart shock in San José. This shock
was felt at Santa Cruz, twenty-five miles west, and was
evidently more marked in strength at that locality. No damage.

September 12th, 19h. 40m.—A smart shock at San Francisco. The
motion was from north to south. There were two vibrations with
undulatory movements lasting about fifteen seconds.

September 26th, 1h. 26m.—A light shock at San Francisco.

November 26th, 0h. 24m.—A heavy shock at San Francisco. This
shock was by far the heaviest during the year, it awoke most
people from slumber and created no little alarm; persons left
their beds and sought cooler situations with less attire
than is usually worn. The iron pillars in the second story
of the custom house have separated from the ceiling above
about half an inch, and are supposed to have settled from the
effects of the shock; I much doubt the alleged cause of this
displacement, as the pillars below present no indication of
similar disturbance. This shock was felt at Oakland ten miles
east of the city, but was not felt at Stockton, Sacramento,
nor Marysville. It was evidently confined to an area of ten or
twelve miles.

1859.

January 25th, 20h. 20m.—A heavy shock of earthquake was felt
in Trinity and Shasta counties. It was felt at Weaverville,
Shasta, and Horsetown.

April 4th, 13h.—Quite a severe shock was felt at San José.
There were several vibrations, apparently from north to south.

August 10th, 22h. 35m.—A smart shock was felt in this city (San
Francisco).

September 26th, 6h. 10m.—A smart shock at San Francisco.

October 5th, 13h. 18m.—A very smart shock at San Francisco.

November 27th, 19h. 15m.—A light shock at San Francisco.

December 1st, 0h. 50m.—A smart shock at San Francisco. Felt at
Oakland and Benicia.

December 1st, 14h. 10m.—Several successive shocks were felt at
San Bernardino; several of them were quite heavy, causing much
alarm. No damage was done.

Whole number of shocks during this year was eight.

1860.

During the year last past this portion of the Pacific coast has
been but little disturbed by earthquakes. There have been but
three during this period that can be well authenticated, and
one, viz.: December 21st, whose character is somewhat doubtful.

The shocks that have occurred are as follows:

March 27th.—A severe shock was experienced at Los Angeles and
vicinity, which was not productive of any damage to person or
property. No time is given in the account.

March 15th, 11h.—A violent shock was experienced at Sacramento;
the wave passed through the counties of Placer, Nevada, El
Dorado and Plumas. At Iowa Hill the church bells were rung,
also at Sacramento. At the latter place and at Forest City,
clocks, in many of the buildings, were stopped. This earthquake
extended to the eastern base of the Sierra Nevada. At Carson
City it occurred at 10h. 45m. and very violent; goods were
shaken off the shelves in many of the stores, and a general
panic and stampede prevailed.

November 12th.—A smart shock was felt at Humboldt Bay and its
vicinity, but no damage was done.

December 21st, 6h. 30m.—At San Francisco a series of light
vibrations of the earth occurred, which continued with but two
remissions for the space of half an hour. These vibrations
were not perceptible to persons in the building otherwise than
by mercurial column, which was equal to seven inches of the
barometer, and was the mercury gauge of an air pump that had
remained stationary at twenty-four inches for the space of four
hours. At this time the column in the gauge began to show much
disturbance by oscillating up and down in a very rapid manner
without any apparent cause; the stop screws (Faraday’s) were
all tried at the moment and found perfectly tight as they had
remained for hours previous.

The oscillations were watched carefully by Mr. J. Roach and
myself for half an hour, at which time they ceased. The maximum
of the mercury column was a fraction over an inch, which was
attained through vibrations of one-fourth to one-eighth of
an inch rapidly repeated and continuous, and as gradually,
through a series of lighter vibrations, the displacement would
diminish and the column subside to its former level; this was
three times repeated, the column at no time being at rest. The
period of time occupied by the column in reaching its maximum
of disturbance each time was from eight to twelve minutes.
There was no apparent cause for this disturbance, unless it
be attributable to a series of light vibrations of the earth
occurring in a vertical direction, and to that cause I am
disposed to assign it.

The passing of carriages on the street did not affect these
vibrations of the column, for they continued in the same manner
when those vehicles were not passing. While the oscillations
were going on, I took a sledge and struck some half a dozen
blows on an anvil block in the workshop, which did not make any
perceptible difference in the movements of the column; after
it had come to rest, the same experiment was repeated, but
the column did not in any manner react to the concussion thus
produced.

1861.

During 1861 there has been but one earthquake recorded in the
State.

July 4th, 16h. 11m.—A severe shock of earthquake occurred at
San Francisco. It consisted of three distinct waves following
each other in very rapid succession. Its effects to the east
of the city in the San Ramon Valley were more severe. Near the
house of Mr. Larabie it opened a large fissure in the earth. In
the vicinity of Mr. Porter’s it opened a new spring of water,
and a small running stream was also caused near Mr. Hunt’s. For
several days after, light shocks were repeated at intervals.

1862.

September 29th, 15h. 5m.—A very smart shock of earthquake at
San Francisco. This was felt at Petaluma.

December 23d, 20h. 19m.—A smart shock at San Francisco.

1863.

During the year 1863 we have had five earthquakes, and unmarked
by any serious event.

January 25th, 2h. 20m.—A severe shock was experienced at San
Diego, continuing from five to eight seconds. There was no
undulation in this instance, the shock consisting of a series
of sharp jars. It was preceded by a profound rumbling sound.

February 1st, 16h. 1m.—A very smart shock at the Mission San
Juan, Monterey County. At Gilroys the shock was felt (or
another) fifteen minutes later. The latter town is near twelve
miles east of the Mission. At both localities the motion was
undulatory. The shock was not felt at Monterey, twelve miles
west of San Juan.

June.—A smart shock at San Francisco.

July 15th, 10h. 19m.—A smart shock at San Francisco.

August 1st, 11h. 6m.—Two light shocks at San Francisco about
one hour apart.

December 19th, 12h. 38m.—A very smart shock was felt throughout
the city; directly afterwards another and more severe one
occurred. The first was a sharp, sudden jar, the second
undulatory. The accuracy of the telegraph operator at Santa
Clara enables us to form a correct idea of the course of this
wave. His time was 14h. 44m. 31s., and within twenty-nine
seconds of true time. The elapsed time is 7m. 31s., and gives
for the direction of the seismic wave a course north and south
(in lieu of east and west in my first notice which was thus
in error.) I take this opportunity to express the thanks of
the Academy to this operator for his accuracy and kindness in
furnishing us dates in this and other phenomena of scientific
and public interest.

The figures derived from our statistics furnish us the
following interesting results as to the frequency of shocks in
one season of the year more than in another. The tables below
furnish the details.

It is found from these figures that during the thirteen years
ending December, 1863:

_First._ The number of days on which earthquakes have occurred,
is one hundred and ten.

_Second._ The month in which the greatest number have occurred
is January, being sixteen; and the months in which the least
number have occurred, is April and February, the sum of each
being six.

_Third._ The winter months have given the largest number in
the aggregate, the sum being thirty-four. The summer months
the smallest number; their sum being twenty-three. The
spring months have given twenty-four, and the autumn months
twenty-nine.

_Fourth._ The number of shocks between the equinoxes foot up
thus. Between the autumnal and vernal equinoxes the sum is
sixty-four; between the vernal and autumnal equinoxes, the sum
fifty-two.

_Fifth._ The number of shocks that have taken place between the
solstices stand thus. From the winter to the summer solstice
the sum is fifty-four. From the summer to the winter solstice,
the sum is fifty-nine.

TABLE 1.—_Giving the number of shocks in each month of the
year, for thirteen years._

-------+----+----+----+----+----+----+----+----+
TABLE. |1850|1851|1852|1853|1854|1855|1856|1857|
-------+----+----+----+----+----+----+----+----+
Jan. | | | | 1 | 1 | 2 | 5 | 4 |
Feb. | | | | 1 | | 1 | 1 | 1 |
March | 1 | | | 1 | 2 | | 2 | 2 |
April | | | | 2 | 1 | 1 | 1 | |
May | 1 | 3 | | | 2 | | 2 | 2 |
June | 1 | 1 | | 1 | 1 | 1 | | 1 |
July | | | | 1 | 1 | 2 | | |
August | 1 | | | | | 1 | 2 | 2 |
Sept. | 1 | | | 1 | 1 | | 2 | 2 |
October| | | | 2 | 2 | 2 | | 1 |
Nov. | | | 1 | 2 | | | 1 | 1 |
Dec. | | 2 | 1 | 1 | | 2 | | 1 |
+----+----+----+----+----+----+----+----+
Total. | 5 | 6 | 2 | 13 | 11 | 12 | 16 | 17 |
-------+----+----+----+----+----+----+----+----+

-------+----+----+----+----+----+----+------
TABLE. |1858|1859|1860|1861|1862|1863|Total.
-------+----+----+----+----+----+----+------
Jan. | | 1 | 1 | | | 1 | 16
Feb. | 1 | | | | | 1 | 6
March | | | 1 | | | | 8
April | | 1 | | | | | 6
May | | | | | | | 10
June | | | | | | 1 | 7
July | | | | 1 | | 1 | 7
August | 1 | 1 | | | | 1 | 9
Sept. | 4 | 1 | | | 1 | | 13
October| | 1 | | | | | 8
Nov. | 1 | 1 | 1 | | | | 8
Dec. | | 2 | 1 | | 1 | 1 | 12
-------+----+----+----+----+----+----+------
Total. | 7 | 8 | 4 | 1 | 2 | 6 | 111
-------+----+----+----+----+----+----+------

TABLE 2.—_Number of shocks occurring between the dates of the
equinoxes and solstices, for thirteen years._

-------+---------------+---------------+--------------+-------------
| Sept. 20th to | March 20th to | Dec. 21st to | June 21st to
TABLE. | March 20th. | Sept. 20th. | June 21st. | Dec. 21st.
-------+---------------+---------------+--------------+-------------
1850 | 1 | 4 | 2 | 3
1851 | 2 | 4 | 5 | 1
1852 | 2 | | | 2
1853 | 10 | 5 | 8 | 7
1854 | 5 | 7 | 6 | 6
1855 | 8 | 4 | 4 | 8
1856 | 7 | 9 | 9 | 7
1857 | 9 | 8 | 8 | 9
1858 | 4 | 3 | 3 | 5
1859 | 6 | 2 | 2 | 6
1860 | 4 | | 3 | 1
1861 | | 1 | | 1
1862 | 1 | 1 | 1 | 1
1863 | 3 | 3 | 3 | 3
-------+---------------+---------------+--------------+-------------
Total | 64 | 52 | 54 | 60
-------+---------------+---------------+--------------+-------------

I regret that my records of the occurrence of earthquakes upon
the east coast of the United States is not more complete than
it is, and also that it does not extend through an equivalent
period of time as our own, from 1850 to date; but I have no
authentic records of their occurrence on the other side later
than 1854; my business at that time, and the subsequent period
that has elapsed, being such that I was not able to maintain
their continuation. In order to prove the statement made on
a preceding page correct as to our relative immunity on this
coast over equal extent of territory, I here subjoin the totals
on both coasts during that period of time. This statement
will also include those shocks which were matters of record
belonging to the West India Islands, and which properly belong
to the eastern-coast series.

The figures relating to this matter, stands thus:

In California during 1850, five shocks; 1851, six shocks; 1852,
two shocks; 1853, thirteen shocks; 1854, eleven shocks. Total,
thirty-seven shocks.

In United States, east coast. 1850, three shocks; 1851, seven
shocks; 1852, ten shocks; 1853, thirteen shocks; 1854, eleven
shocks. Total, forty-four shocks.

Balance against east coast, seven shocks.

West India Islands. 1852, seven shocks; 1853, three shocks;
1854, one shock. Total, eleven shocks.

These inclusive with the continental series foot up eighteen
days on which shocks occurred in excess of this coast during
the same period of time, and thus shows a margin of greater
frequency of little more than thirty per cent.

ERRATUM.

Page 131, line 16 from bottom, for “an oven” read “or even.”

REGULAR MEETING, MAY 2D, 1864.

Dr. Trask in the Chair.

Eleven members present.

Donations to the Cabinet: Specimens of dried plants, the types of species lately described in these proceedings by Prof. Gray.

Mr. Brewer presented for Mr. Gabb the following paper:

On Cretaceous Fossils from Sahuaripa Valley, State of Sonora, Mexico, discovered by August Rémond

BY W. M. GABB.

Mr. Rémond announced in a letter to me, the discovery of
fossiliferous rocks about a league and a half east of Arivechi,
Sahuaripa Valley, Sonora, Mexico. The fossils occur in a clay
slate, and are in a fine state of preservation. He says: “The
shales rest on sandstones, barren of fossils; feldspathic
porphyries protrude through them, but no alteration of the beds
were observed at the points of contact. Even the lamination of
the fossiliferous strata has not been disturbed, and shells
are found but a few millimetres from the porphyry.” He adds
that the fossil bearing strata may attain a thickness of four
or five hundred feet. The shales are overlaid by thick strata
of compact blueish limestone. The strata dip to the south-east
with an inclination of from thirty to fifty degrees, and form
the first range of foot-bills of the Sierra Madre.

I have identified the following species on a hasty examination,
proving conclusively the cretaceous age of the formation.
It is an interesting fact, that the fossils indicate a
closer relationship to the eastern deposits than to those of
California.

Turritella seriatim-granulata Roem. Cardium Tippanum? Con.
Chemnitzia (?) gloriosa Roem. Trigonia Evansii? Meek. Neithea
quadricostata Sow. Exogyra Texana Roem. Turbinolia Texana Con.

REGULAR MEETING, MAY 16TH, 1864.

President in the Chair.

Fourteen members present.

Rev. Mr. Neri, of Santa Clara, was elected a corresponding member.

Donations to the Cabinet: Volcanic cement, from Sierra County, containing fossil wood; also a magnesian mineral, from a cavity in a quartz vein near Nebraska, Sierra County. Mr. Clayton stated that when found it was gelatinous, semi-transparent, and mixed with loose quartz crystals; but on drying it shrank greatly in bulk and became fibrous, like fine Asbestos. The miners say that it is not uncommon in that locality.

Seeds of a large Melon Cactus, from the Colorado deserts; also seeds of a fine nutritious “bunch grass,” from the dry foot hills near Fresno river, by Mr. J. E. Clayton.

Mr. Brewer stated that he had obtained further information regarding the coal brought before the Academy Feb. 15th, by Prof. Blake. On the authority of J. Ross Browne and another gentleman, he had learned that no coal occurs in the locality near the Colorado River then mentioned, and that the specimens were English coal carried up the river by speculators for the purpose of swindling the public by selling stock in a fictitious coal mine.

REGULAR MEETING, JUNE 6TH, 1864.

President in the Chair.

Nine members present.

Donations to the Cabinet: A piece of sandstone resembling in shape a human foot, by Mr. Ed. Webber.

Donations to the Library: American Journal of Science and Arts for March, 1864, from the editors. Observations on the Genus Unio, by Isaac Lea, L.L.D., Vol. 10. How to collect and observe Insects, by H. S. Packard, Jr. Plants of Buffalo, N. Y. and its vicinity, by G. W. Clinton. Bulletin of the Museum of Zoölogy of Cambridge, Mass. pp. 29—60. Report of contributions to the Pennsylvania Relief Association for East Tennessee. Proc. of the Acad. Natural Sciences of Philadelphia from October to December, 1863, and January and February, 1864. Contributions to the Physics, etc. of the Sacramento River, by Thos. W. Logan, M.D., extracted from the Pacific Medical and Surgical Journal, Vol. 7, 1864,—from the author.

REGULAR MEETING, JUNE 20TH, 1864.

President in the Chair.

Eleven members present.

C. W. M. Smith and Dr. McClure, of Redwood City, were elected resident members.

Donations to the Cabinet: A large crab, from the west coast of Mexico, by G. O. Haller, through Dr. Cooper.

Donations to the Library: Report of the Smithsonian Institution for 1862.

ADJOURNED MEETING, JULY 11TH, 1864.

Dr. Trask in the Chair.

Seven members present.

The following paper was received from the author, in accordance with the proposition accepted by the Academy Dec. 7th, 1863.

Descriptions of New Marine Shells from the Coast of California.