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                               OLD MINES
                                   OF
                          SOUTHERN CALIFORNIA


                    _Desert-Mountain-Coastal Areas_
                             _Including the
               Calico-Salton Sea Colorado River Districts
                                  and
                           Southern Counties_

                                  1965
                         Frontier Book Company
                         Toyahvale, Texas 79786

                            _Reprinted From_
                 _The Report of The State Mineralogist
                                 1893_
                        _Limited to 1000 copies_




                          LOS ANGELES COUNTY.


                By W. H. Storms, Assistant in the Field.

The mining industry in this county is not as extensive as that of some
of the neighboring counties, but there are mines in Los Angeles County
of unquestioned value, and others which have a prospective value,
dependent to a great extent upon the success achieved in working certain
base ores, which occur in comparative abundance.


                            THE KELSEY MINE.

One of the most interesting mines in the county is located in the rugged
mountains about 8 miles from the town of Azusa, in the San Gabriel
Cañon. It is commonly known as the Kelsey Mine, and has become famous as
a producer of silver ore of fabulous richness.

The country is made up almost entirely of metamorphic rocks, having
schistose, gneissoid, and massive structure. Both hornblende and mica
occur in these rocks abundantly, the former being frequently altered to
chlorite, or by further change to epidote. Dikes of porphyritic rock
have been intruded into the crystalline schists. In the immediate
vicinity of the Kelsey vein are intrusions of a dark green, much
decomposed, and shattered rock, probably diorite. Faults, great and
small, are numerous throughout the region. Within a few hundred feet of
the mine is a great fault, which may be plainly seen cutting the
mountain. The displacement must reach many hundreds of feet. It has
resulted in bringing in contact on a horizontal plane rocks of entirely
different character. On the south side of the fault the rocks are made
up of quite regularly bedded micaceous sandstones, more or less
schistose, and having a prevailing buff or light gray color. These rocks
dip east at an angle of 20° to 30°. On the north side of the fault the
rocks are harder, of a dark gray color, and containing considerable
hornblende. These rocks are more gneissoid and massive than schistose.
The dip is much less regular than on the south side of the displacement.
Large, lenticular masses of quartzose and feldspathic rock are of
frequent occurrence in the hornblende gneiss, evidently the result of
the segregation of the contained minerals. On the whole there is much
more evidence of the disturbance on the north side of the fault than on
the south side. It is in this area of greatly disturbed strata that the
Kelsey vein has formed.

The vein is of the fissure type and occupies the line of a fault plane,
that at first, perhaps, was a mere crack, but which has become enlarged
by the movement upon themselves of the rock masses forming the walls,
resulting in a grinding and crushing of the rocks by the attrition and
pressure incident to this movement. Into this crevice mineral waters
found their way, carrying in solution the minerals now constituting the
vein.

    [Illustration: _FAULTING AND TORSION
    OF THE
    KELSEY VEIN_]

_The Ore._—The silver occurs as native and as glance (argentite),
possibly partly as chloride and in combinations with sulphur, cobalt,
and arsenic. The associated minerals are cobalt bloom (erythrite), a
hydrous cobalt arsenate, nickel arsenate (annabergite), carbonate and
silicate of copper (chrysocolla), iron oxide, and black oxide of
manganese in a gangue of baryta (heavy spar), with calcite (lime spar)
and some quartz. A clay selvage usually separates the vein material from
the wall, this feature being well developed in places on the foot wall
side, as though open crevices had occurred and the finely divided
material which was carried by the percolating waters had found a resting
place when an open space was reached, the absence of any current
permitting the material to settle.

The clay may have been derived in part from the decomposition of the
overhanging wall, the fine silt settling by gravity on the foot wall
side of the vein. In places a soft, clayey gouge constitutes the entire
vein filling, suggesting that the clay selvage and gouge are also partly
due to the attrition of the walls. Galena occurs sparingly in small
disseminated crystals, but the occurrence is so infrequent as to be
scarcely worth mentioning. In width the crevice varies from a thin seam
to over 4 feet. A banded structure is not uncommon in the vein.

The rocks inclosing the vein differ in various parts of the mine. A much
decomposed rock, containing iron in the form of carbonate, occurs
frequently, while a chloritic, more or less schistose, sometimes
massive, rock, also plays an important part in this connection. The dike
of dark basic rock, resembling diorite, previously referred to, is
exposed at numerous places throughout the workings, often in contact
with the vein, or close to it. Since its formation the Kelsey vein has
been subjected to severe torsion, which has resulted in abrupt fracture
and displacement. To me it seemed very probable that the vein was the
result of chemical precipitation, and no doubt, to some extent, the
replacement of country rock along the line of a fissure or fault plane;
that subsequent to the filling in of the vein the region was subjected
to further violent disturbances, which fractured the rocks along an east
and west course, and causing the turning of a large mass of rock
formation lying south of this fault to the west. The vein being included
in the general movement, was deflected from its natural course north and
south. I came to these conclusions from close observations taken along
the surface of the ground on the course of the vein, and in all
accessible underground workings.

Most of the ore extracted from these workings has been high grade,
usually running over $200 per ton, small lots often assaying several
thousand ounces. The property, at the time of my visit last spring, was
under the management of Dr. Endlich, E.M. This gentleman was making
every effort to systematically open and recover a vein that had been as
systematically and outrageously gouged. The workings were in bad
condition and at some points were positively dangerous. The mine was
gradually assuming an improved appearance and promised to yield better
returns than ever before. A good mill has been erected at the foot of
the mountain, in the San Gabriel Cañon, where a large stream of water
flows during the entire year. An office, boarding house, stables,
corrals, etc., had been built for the accommodation of men and animals.
In addition to this I found a complete assay office and chemical
laboratory, and here Dr. Endlich was experimenting with the rich cobalt
and nickel ores. As a result of his labors in this direction he
exhibited several bars of cobalt speiss containing a very high value in
silver. The assorted ore contains from 7 to 15 per cent in cobalt, 2 to
3 per cent nickel, and from 1,000 to 1,400 ounces silver per ton.

Dr. Endlich thus describes his methods: “The ore is crushed through a
twenty-mesh sieve, mixed with sufficient litharge to produce an 8 per
cent charge, and enough borax is added to take up the gangue (quartz,
heavy spar, carbonate of lime, magnesia, and iron). Carbonate of soda
and flour are mixed with the charge. If the percentage of arsenic in the
ore is sufficiently high to produce speiss none is added; otherwise some
metallic arsenic is mixed in. Some sulphides in the ore and reduced
sulphur from the heavy spar are utilized to produce mattes. The mixture
is melted in large Dixon crucibles; the slag poured off, and the
metallic product allowed to cool. The bars obtained are composed of
lead, silver, cobalt, nickel, arsenic, and sulphur, principally; the
lead being in the form of sulphide, the cobalt and nickel in the form of
arsenides. The bars contained from 4,500 to 7,000 ounces silver per ton.
The slag contained a trace of silver, and averaged about 0.75 per cent
cobalt, which can be worked over by arsenizing, if desired, and the
cobalt obtained in the resulting speiss.”

At this writing about 560 pounds of ore has been treated in this way and
the product shipped to Balbach’s works in Newark, N. J., for refining.


                          THE VICTORIA MINES.

This property is situated but a short distance from the Kelsey Mine. The
Victoria Mine was operated under English management for an English
syndicate two or three years ago. Lately all operations have been
suspended. The property, whatever it may be worth, is a monument to
mismanagement of the worst sort.


                        THE LORDSBURG STAMPEDE.

In the month of March, 1892, the report went abroad that rich silver and
gold-bearing rock had been found in the mountains north of Lordsburg, 28
miles east of the city of Los Angeles. So glowing were these stories
that a general stampede for the new mining field ensued. Farmers left
their homes, merchants and clerks in some instances temporarily closed
their stores to join in the rush to Lordsburg. Unfortunately the stories
proved to be unfounded, and, after three weeks of excitement, all had
left the mines excepting a very few, who still had hopes of making a
find.


                         CEDAR MINING DISTRICT.

Fifty-five miles by rail northeast from Los Angeles, on the line of the
S. P. R. R., is the Cedar Mining District, the principal village being
about the railway station called Acton. In the low hills about Acton,
which rise out of the valley that skirts the northern base of the San
Gabriel range of mountains, are located the gold mines which have been
worked for many years by Mexicans and Americans.


                             THE RED ROVER.

This is the name of the principal mine in the district. It was located
and worked many years since by Mexicans, but has during the past eight
or ten years been in the hands of Americans. The vein strikes northwest
and southeast, dipping to the southwest at an angle of 50° from the
horizon. The rock is a white, fine-grained, saccharoidal quartz, showing
in places bluish bands. It contains free gold in variable amount, with
some iron sulphuret. A very large amount of quartz has been stoped from
the vein and crushed in various mills.

The Red Rover is quite extensively developed, the new vertical shaft
being down over 400 feet. The old inclined shaft, which is sunk on the
vein, is down 220 feet. Several levels are run out from both these
shafts, which are 200 feet apart. The new shaft was sunk between the
main vein and a spur which branches from it. A crosscut was run out
toward the spur, which is opened on the surface, but it was found it did
not go down. A crosscut was then run toward the main vein, which was
found intact, and a drift was carried in 60 feet on the vein.

The country rock is mostly massive metamorphic, very much broken and
faulted. Nearly every mine in the district has been displaced more or
less by these faults. For some reason the Red Rover has been shut down
for some months past. It is understood that operations are to be
resumed.


                           THE NEW YORK MINE

Is situated within half a mile of the Red Rover, and is similar in
character. The quartz is said to mill $10 to $25 per ton. The owner has
a five-stamp mill, which is complete and does good work. The vein is
from 1 to 3 feet in width. It has produced considerable bullion.

Other mines of the vicinity are the Topeka, Union, Escondido, King of
the West, and Santa Clara, each of which has seen better days. The first
three mentioned have been large producers, but are worked down to the
water line, and a base ore proposition now faces the owners in the form
of iron pyrites.


                           IN THE MAIN RANGE.

Up in the main range of the San Gabriel Mountains, on the north <DW72>s
of this rugged chain, are located a number of veins, on which
considerable work has been done. The veins are well defined, ranging
from 1 to 4 feet in width, striking northwest and southeast, and dipping
uniformly to the northeast at a high angle. All of these veins contain
gold, but all quickly run into sulphurets. All the mines are idle at
present, but something brighter is hoped for. The sulphurets are said to
contain sufficient gold to make chlorination profitable. If this is
actually the case there is an abundance of material to work upon.


                          LIPARITES AND TUFAS

In the region about Acton are many hills of liparite (quartz-bearing
trachyte) and tufa, which are identical with the rhyolites of the Calico
region—the same violet-brown, porphyritic liparite; the same pea-green
and buff- tufas; the same conglomerate; in fact, an exact
facsimile of the Calico range. There are no great beds of sedimentary
rock, however, and these liparite hills are comparatively small,
isolated masses. As far as my knowledge goes ores of silver have never
been found in these rocks in the Acton district. Careful prospecting may
possibly discover such ores.


                         PROSPECTS OF THE CAMP.

Owing to the fact that the gold mines of this district have been worked
to the water line, almost without exception, what now remains to be done
to perpetuate the prosperity of the district, is to concentrate the
sulphurets, working them by chlorination in works built in the district.
Wood and water are both obtainable at moderate cost, and the
sulphuretted ores of this district that contain but a very few dollars
per ton should pay. The cost of mining, transportation, crushing, and
concentrating should not exceed, ordinarily, $5 per ton of quartz, and
the expense of treating the concentrates should be under $10 per ton.
Base ores containing $10 per ton as it comes from the vein should
realize a profit in this district, and I am told that many of the mines
produce rock of a much better grade than that mentioned.




       SAN DIEGO COUNTY; ALSO ORANGE AND SAN BERNARDINO COUNTIES.


                    By Harold W. Fairbanks, F.G.S.A.

The topography of this region has been quite thoroughly described by W.
A. Goodyear, in former reports of the State Mining Bureau. The structure
of San Diego County is comparatively simple. Three main divisions might
be made: the desert on the east, the Peninsula range of crystalline
rocks in the middle, and the nearly level mesa on the west. The
Peninsula range is supposed to represent the southern continuation of
the Sierra Nevadas, but in just what relation it stands to the Sierras
has been a matter of dispute. The Peninsula range in San Diego County
forms one main mountain chain. It maintains this simplicity of structure
southward, forming the backbone of the peninsula of Lower California.
Northward it becomes broader and more complex, rising in the lofty San
Jacinto and San Bernardino ranges on the east, and the Santa Ana range
on the west, while the region between is filled with mountains and
valleys irregularly disposed.

Complex as is the topography of this region, the geological problems,
though often difficult to solve, are quite simple. The higher mountains
are formed wholly of ancient crystalline schists and massive rocks,
respecting the age of which a great diversity of opinion has existed;
while the region bordering the coast consists of unaltered Cretaceous,
Tertiary, and Quaternary deposits.

Owing to the very limited time given me to prepare my field notes for
the press, they will be given substantially as they were taken in the
field, without any attempt at systematic arrangement.

The crystalline rocks of San Diego County are varied in character, and
of much interest. No opportunity has been given me to study the large
collection made, and the determinations given are simply the result of
superficial examination, and are subject to correction.

The bay of San Diego is bordered on the east by gently sloping mesas of
modern Tertiary and Quaternary age. These unaltered strata are
characteristic of the western <DW72> of the Peninsula range through its
whole extent. They sometimes rise as high as 3,000 feet; though in San
Diego County they do not exceed 1,500 feet. The upper portion of these
beds consists to a great extent of coarse, loosely cemented
conglomerates. The rivers issue from the higher mountains through narrow
valleys or cañons, and have cut valleys, often quite broad and with very
steep sides, through the mesas to the ocean.

The Otay mesa has a height of about 500 feet, the western portion being
somewhat higher than the eastern, indicating a recent elevation near the
coast. The soil of the mesa is adobe, due to the decay of porphyry
mountains to the east. Under the adobe there is a calcareous marl, often
many feet thick.

The first exposure of the older rock seen as one goes up the Otay River,
is in a hill rising through the mesa about in the center of the grant.
It is a part of the extensive porphyry intrusives, which, in southern
San Diego County, form a number of high mountains between the granite
and the mesa. To this formation belong the San Miguel and Otay peaks.
This exposure on the Otay River is a felsitic breccia. It contains a
felsite base (intimate mixture of quartz and feldspar), in which are
imbedded fragments of felsite and chlorite. No more rocks appear for
about 2 miles up the river. Then we reach the base of the long ridges
which lead up to the Otay Peak. Some interesting rocks are exposed where
the stream issues from the cañon. The greater portion are fine dark to
greenish aphanitic rocks, with green chloritic or epidotic nodules.
Bunches and dikes of coarse to fine grained porphyritic rocks
occasionally appear. They probably belong to the diorite porphyrites.
The rock continues very much the same for several miles farther east; at
times it is almost wholly feldspar. In the cañon above El Nido Post
Office it changes to a light green feldspar porphyry. Near the western
edge of the Jamul grant a dark- porphyry takes its place, and a
little farther east it becomes jet black, with small white feldspar
crystals, producing a very pretty effect.

The mesa conglomerates extend along the top of the low hills bordering
the valley nearly to the eastern edge of the Jamul grant. A great
variety of rocks appear along the Campo road between the Jamul grant and
Sheckler’s, on the Cottonwood. Near the eastern end of the grant the
porphyry is followed by fine-grained granitic rock, frequently becoming
schistose. Numerous dikes and bunches of dark diorite cut through this
rock. As Dulzura Post Office is approached, these rocks change to mica
and hornblende schists, and are filled with intruded dikes of diorite
porphyrites. Bodies of massive syenite and coarse granite were also
seen. About Dulzura many of the dikes have the appearance of diabase.
Between Dulzura and Sheckler’s the country rock is largely micaceous and
chloritic schists. Massive granite forms the high, rugged mountains
east, extending in an arm westerly across the road. The schists have a
northwest strike, vertical dip, and are evidently of metamorphic origin.
They form a strip of country extending in the line of strike from near
Sheckler’s to the Sweetwater River, and are situated between the wide
belt of porphyry on the west and the coarse intrusive granites on the
east, which rise to form Lyon’s Peak and other rugged mountains.

The first rock met east of Sheckler’s, on the Campo road, is coarse
hornblendic granite, so decomposed that a fresh specimen could not be
obtained. Dikes of fine-grained granite intersect it in every direction.
Three miles west of Potrero, mountains of olivinitic diabase rise on the
north side of the road. This rock is very similar to many large bodies
of intrusives through the mountains between Julian and the Tia Juana
River. It has evidently been intruded into the granite, for dikes extend
out, intersecting the latter rock.

Potrero is located in a valley of several hundred acres in extent, and
surrounded by granite mountains. It has an elevation of 2,400 feet.
South of Potrero, along the boundary line, the mountains show large
areas of the dark dioritic and diabasic rocks. The hills immediately
south of the valley consist of hornblendic gneiss; strike east and west.
Eastward, toward Campo, the rock is chiefly a coarse white granite, very
easily decomposed. It shows a slightly gneissoid structure for a number
of miles. It does not seem to represent the bedding of a sedimentary
rock, but of parallelism of the constituents, induced in the magma by
movement or pressure. Long, drawn out, lenticular inclusions are often
present, and are arranged parallel to the schistose structure. These
consist largely of hornblende, with little feldspar.

In the vicinity of Campo the topography of the country changes from that
of high mountains and deep, narrow valleys, to an elevated mountain
plateau with meadows and rounded granite ridges. The mountains are
covered with brush, while live oaks are numerous in the valleys. The
country maintains these features while gradually rising to the divide 8
miles east of Campo. The granite is so deeply decomposed along the
summit region that no good samples could be obtained. Campo has an
elevation of 2,600 feet. The bare, rounded ridges closely resemble those
left by glacial action, but their <DW72> is produced simply by the
cleaving off successively of the more angular portions in great slabs.
Many fine examples of this manner of decay appear about Campo. The
corners are decomposed faster than the smooth surfaces, and thus finally
a shelly concentric structure results. The fresh massive central portion
weathers out like water-worn bowlders. The presence of rugged angular
ridges results either from a less inherent tendency to decay, or to a
comparative freedom from crushing. Four miles northeast of Campo is an
outcrop of coarse hornblendic granite, with large six-sided mica scales
and numerous yellow crystals of titanite. The height of the divide is
3,800 feet. Near the summit the rocky ridges all disappear and the
country becomes covered with granitic sand. Erosion here is evidently
very slight. The country descends gradually on the east to Jacumba
Valley, being sandy for some distance. This finally gives place to bare,
rocky ridges and cañons. Veins of fine granite, and others of feldspar
and quartz, are abundant on the eastern <DW72>.

Before reaching Jacumba Valley a body of mica and hornblende schist is
encountered. The schists do not form a regularly defined belt, but often
appear as inclusions in the granite. These inclusions have a very
variable strike, and from their relation to the granite it is evident
that the latter is intrusive.

Jacumba Valley empties northward into the desert through a narrow gorge.
It has an elevation of 2,600 feet, the same as that of Campo. It is
several square miles in extent, the greater part of which is in Lower
California. The warm springs here are considered quite medicinal. The
schists just described occupy a large area west and north of the cañon
through which the valley empties. They are cut in every direction by
dikes of granite and others, consisting of a very coarse aggregate of
quartz and feldspar with a little muscovite mica. A high mountain
several miles north of the valley is distinctly ribbed all over by them.
The schists extend northward toward those which outcrop on the eastern
<DW72> of the Laguna Mountains and at Julian, but are cut off by a body
of intrusive granite. They undoubtedly belong to the same series.
Gold-bearing veins have been found in them a little north of Jacumba
Valley.

At the north end of Jacumba Valley, and on the west side of the outlet,
is an area of volcanic rock, probably basalt. It forms a table-land,
gently sloping toward the valley, and rising 600 or 700 feet at its
northern end. It is underlaid by gravels and conglomerates. Just east of
this is a black butte, rising perfectly symmetrical to the same height.
It consists of bedded lavas, with tufa at the bottom. In spite of the
fact that it is shaped like a crater, its structure is different, and it
is probably a remnant of the flow which once covered the outlet to the
valley.

The high range of mountains between Jacumba Valley and the desert has an
altitude of something over 4,000 feet, but where the road crosses it, it
is only 3,100 feet. Basalt outcrops also on the eastern side of the
valley. North of the road to Mountain Springs it forms a series of
plateaus, the highest of which reaches a height of 3,900 feet. It forms
the summit of the range, being 800 feet above the granite forming the
pass. South of the pass several miles the granite rises much higher and
the lava lies along its western <DW72>, extending an unknown distance
below the line.

Large deposits of water-worn bowlders and gravels lie along the eastern
<DW72> of Jacumba Valley. Among them are pebbles of porphyries, black
quartz, and others not seen in place in this part of the county. A short
distance west of the summit they are found in beds with gravel and
sandstone, dipping southwest. These late Tertiary deposits are overlaid
by the volcanic beds. The volcanic plateau which rises so high north of
the pass has a thickness of 500 to 600 feet. Massive and bedded lavas
form the upper half of this thickness, the lower portion consisting of a
volcanic breccia. The beds lie nearly horizontal. On the west are two
lower terraces, also capped with lava and abutting against the higher.
The whole is underlaid by sand rock of granitic origin. It is nearly
level in places, in others it dips to the southwest. It is very strange
that these lava beds, with nearly level flowage lines, should be found
at such greatly varying elevations about Jacumba Valley, and be
underlaid everywhere by such similar tuffs and sandstones. My
investigations disclosed no volcanic vent, and it is possible that the
lava issued from fissures, as was noticed elsewhere in the county.
Another interesting question is the origin of the sandstones and
conglomerates. The sandstone underneath the high plateau is higher than
the divide at that spot, and the only granite within miles that exceeds
it in height, is the narrow ridge which rises on the southeast. The
erosion must have been very great along the ridges since the sandstones
were deposited, but the valley cannot have changed much. There may have
been great elevation along the crest of the range bordering the desert
since the deposition of sandstone, tilting up the sandstone and lava on
the eastern <DW72>, but elevating without great disturbance those near
the summit. Southeast of Mountain Springs is a body of bedded tufas
reaching an elevation of 2,300 feet, and dipping to the east away from
the range at a considerable angle.

The presence of these modern sandstones at so great an elevation nearly
on the crest of the Peninsula range is a very interesting fact. Either
Jacumba Valley was a lake, or a great elevation has taken place in
comparatively recent times, raising the valley from the sea-level.
Appearances indicate that during late Tertiary times this range was
almost submerged beneath the sea.

The rocks between the summit and Mountain Springs are chiefly gneissoid,
at times granitic. They contain bodies of fine dark mica schist, and
many dikes of very coarse muscovite granite. The descent to the desert
is very abrupt over bare granite ridges. Mountain Springs, an old stage
station, is located on the side of the mountain at an elevation of 2,300
feet. From the springs the road descends along the dry bed of an arroyo
to the desert. The most of the distance is through a rocky cañon, where
there is an excellent opportunity to study the relations of the gneiss
and granite. For some distance down from the springs the rocks continue
to be gneissoid, but through the lower end of the cañon they become more
massive and coarse, and all the veins characteristic of the gneisses of
the higher mountain region disappear. At the upper end of the cañon is a
dike of very coarse granite, with large biotite crystals instead of
muscovite. This is the only instance in which biotite was seen in one of
these coarse dikes. Banded gneiss, varying from very thin to very thick
bedded, alternate with other rocks, to all appearances massive granites,
but in surface decay the latter break up into slabs of varying
thickness, parallel to the schistose structure of the gneisses. The
banding is caused by an excess of mica or hornblende, chiefly the
latter, arranged in parallel layers. These strata are often very thin,
varying from one fourth to one half inch and upwards in thickness. They
are very regular, but often discontinuous; stop, and in course of a few
feet begin again. These features are generally supposed to indicate
metamorphic origin, but at one spot a body of dark mica schist is cut by
a dike a foot wide or more of this dark banded gneissose rock. This dike
cuts across the stratification of the mica schist, showing conclusively
the intrusive nature of at least a part of these gneisses; and it is
quite possible that the inclusions of mica schist are the only really
sedimentary rocks present. In places the rocks which show this banding
have the constituents arranged in the bands independent of any
direction. At one spot a distinct, well-defined mass of mica schist, 15
feet across, is imbedded in a granitic rock. At one side this gneissoid
structure extends through the inclosing rock and abuts sharply against
the mica schist. The banding shows no constant direction; in the cañon
it is northeast. The bands sometimes become wavy.

As the cañon opens out to the desert, hills appear on either side formed
of volcanic tuffs. They dip northeast 30°. Underneath is a sandstone
wholly unconsolidated and dipping in the same direction 40°. This
contains no lava pebbles. The fragments of the tuff are quite varied in
character and generally quite angular. They are imbedded in a volcanic
mud, free from granitic detritus. In some of the strata appear thin beds
of lava, seeming to represent a flow. These tufa hills extend
northwesterly along the base of the granite mountains for 10 miles or
more. It is not known how far they go in a southerly direction. In
places they form mountains of considerable size high up on the side of
the range. The range of mountains between this point and Carrizo Creek
appears also to have some volcanic beds on its southern <DW72>. The open
desert at the foot of the mountains has an elevation of 1,200 feet. It
<DW72>s gently for miles in an easterly direction and consists largely of
loose sand.

Between Mountain Springs and the summit is another illustration of the
fact that lamination in a crystalline rock is no proof of its
sedimentary origin. A small dike less than 2 inches thick cuts across a
coarse biotite gneiss at an angle of 30°. It is separated from the
gneiss by a thin layer of quartz and feldspar. It is made up of the same
constituents as the gneiss, arranged so as to show a well-pronounced
gneissoid structure. This is very similar to the large dikes seen in the
cañon.

The road was followed back to Campo, and from there the Laguna Mountains
were climbed. The road ascends a long, narrow cañon on the southern
<DW72>. At the entrance to the cañon, 4 miles southeast of Buckman’s
Springs, the mountains are high and rocky, being formed of thin-bedded
gneisses, which, in many places, blend into mica schists