Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 5, Pt. 2

APPENDIX.
DESCRIPTIONS OF SEVERAL OF THE SPECIMENS.
No. 1. Granite, with hornblende and mica, summit of the Tejon Pa8s.-This is a bard, compact rock, being a mixture of feldspar and hornblende in nearly equal parts, together with
mica, which is not found in regular, detached crystals, but is disseminated in minute broken
scales, which form films traversing the mass. A very decided structural arrangement of the
minerals is apparent on the slightest inspection. They are all disposed in nearly parallel
planes. The hornblende so far predominates that it imparts its color to the mass, and the
feldspar appears as white disseminated grains. In color, the hornblende is dark-green, and is
found in irregular crystals of various sizes, from a mere point to one-quarter of an inch in
diameter. The mica has a dark bronzy-brown color.
No. 2. Compact granite rock, Tejon Pass, near Station 15.-This rock breaks up into rhombic
and triangular masses, and is described in detail in chapter XV. The specimen is triangular,
and shows the structure and- composition of the whole rock very nearly.
No. 3. White, crystalline limestone, Tejon Pass.-This white limestone has such a beautifully
even grain, and such a brilliant white fracture, that its adaptation to building purposes is at
once apparent. There are no lines of structure in the specimen, and it is very homogeneous in
its composition. It does not, therefore, present in itself any good evidence of a stratified origin.
No. 4. -Ietamorp7hic sandstone, Tejon Pass, adjoining the limestone, (No. 3.)-This specimen
is grayish-white, and, although perfectly compact, has a peculiar granular structure and appearance. It looks like a hard silicious sandstone, but the grains are all closely united, so that they
cannot be detached, and they do not feel sharp and harsh to the touch. When examined by
the magnifying glass, many small transparent or translucent grains of quartz are seen. On
one of the weathered surfaces there are many minute cells or pits, apparently formed by the
decomposition of one of the composing minerals. One of the pits is rectangular, and may
have been occupied by iron-pyrites. A fragment, on being treated with chlorhydric acid,
effervesces slightly. It is probable that this rock is a metamorphosed calcareous sandstone.
No. 5. Limestone, enclosing crystals of garnet-Tejon Pass, eastern base.-The color of this
limestone is not pure white, but is yellowish gray or drab. Its grain is not so even and brilliant as that of the limestone found further west, (No. 3.) The mass of the rock also appears
much shattered and broken, and it is traversed with small seams and veins; the walls of some
of them being lined with long crystals of calcite. A large number of brown crystallization are
also present in the specimen. These crystals are regularly formed rhombic dodecahedrons, and
fuse readily before the blow-pipe flame to a vitreous globule. They are in all probability
garnets; but they are not sufficiently compact and lustrous to be interesting as specimens.
No. 10. Granite, July 23.-This is a coarse grained rock,-consisting of flesh-red feldspar and
a dark brown mica, with a little hornblende and quartz. The minerals are dispersed in layers,
but the structure is not very distinct.
No. 11. I'errugitnoubs state-TFrom the walls of the bed of iron ore, Burns' creek, July 22.-This
slate is so highly charged with iron, that it may be regarded as an iron ore; but the distinct
lamellar structure of the slate is preserved. It has the dark brown color of the pure ore, and
can be distinguished from it on inspection, only by its structure and lower specific gravity.
The next specimen (No. 12) exhibits thle slaty character perfectly, breaking into flat slabs and
leaves. It has a bluish-gray, or mouse color, on freshly broken surfaces. Small rusty cavities
spread over the surface -indicate the former presence of iron pyrites. These cavities are not
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