EA A 
APPENDIX, 355 
DESCRIPTIONS OF SEVERAL OF THE SPECIMENS. 
No. 1. Granite, with hornblende and mica, summit of the Tejon Pass.—This is a hard, com- 
pact 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. Metamorphic sandstone, Tejon Pass, adjoining the limestone, (No. 3.) —This specimen 
is grayish- white, and, although perfectly compact, has a peculiar granular structure and appear- 
ance. 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 bril- 
liant 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 walle af some 
of them bein g lined with long crystals of calcite. A large number of brown crystallizations 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 mideper 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. Ferruginous slate— From 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 PETE org 
can be distinguished from it on inspection, only by its structure and lower specific gravity. 
The next specimen (No. 12) exhibits the slaty character perfectly, breaking into flat slabs and 
leaves. It has a bluish-gray, or mouse color, on freshly broken surfaces. Small tty cavities 
spread over the surface indicate the former presence of iron pyrites. These cavities are not 
