301 [ 174 J 
a a ge ospathic.. praniies wih a small proportion of quartz, and sm 
mica in small sc e specimen contains a single e garnet. 
ture is T abuew Lak sin, pi from appearances it Is tapidly destruetibte 
from atmospheric a c 
Longitude 117°, latitude 444°.—These specimens from Brulé river are 
numbered 4, 19, 41, and 48. 
No. 4 is a slaty limestone, partially altered, probably from the proximity 
i igneous rocks. 
No. 41 is of ditaitar character, very CARTE laminated, and ofa dark 
color 
No. 19 is of similar character, but more altered, and paitially crystalline. 
The lines of deposition are, however, phot ved. 
No. 48 has the appearance of a compact gray feldspathic lava ; but there 
are some apparent lines of deposition still visible, which incline’ me to the 
opinion that it is an altered sedimentary roc 
Longitude 1173°, latitude 45°.—The spécimen i is a compact, dark-colored 
basalt, showing a tendency -to et argenie Bpor the exposed surfaces. 
This rock forms the mowntains of Brulé r 
Longitude 1173°, latitude 453°.—The s écimen No. 110isa fine-grained 
basalt or trap, with a few small-cells filled with analcime. This is of the 
rock forming the Blue mountain 
Longitude 118°, latitude 45°. —The single ae (No. te ores this 
locality is apparent an, altered siliceous slat markec ap 
a to be lines of deposition, the thin eehiie being separated BP sm of 
ne aba sit salpnds 384°.—The specimens Nos. 14, 23, 45, and 51, 
are all from this 
No. 14 appears we be a decomposed feldspar, paving a slightly porous 
structure ; it is very cea and adheres eine o the 
No. 23. A friable, mewhat poro S upon the ex- 
posed surfaces. 
No. 45. A see es of a sieniie i poo containing © obstifen. 
This specimen ar much like som us ot gy of. trap dikes 
which cut through. the sienitic rocks of N ew Engl 
No. 51. Feldspar, wie a. little black mica he specimen i is probably 
from a granite rock, though its structure is. that of compact fe dspar. 
Longitude 120°, latitude 453°.—The single specimen (No. Er foun this 
locality i isa = fine-grained trap, or basalt, with a few round cavities 
of the size of 
neers 12045, latitude 383°.—The -speciiaens are numbered 91, 109, 
nd 1 
an 
No. ao has the appearance ofa porous trap, or basalt, though possibly 
the production of a modern voleano. It is thickly spotted with crystals of 
cime, ane apparently segregated from the mass, and others filling ve- 
sieuler cavitie 
oO. 117isa canal basalt, the specimen exhibiting the character of the 
basalt _ — Hudson and Connecticut river valleys. 
No. 109 is a fine-grained granite, consisting of white quartz and. feldspar, 
with black mica. Captain Frémont remarks that this rock forms the east- 
era a Past of the main California mountain. From its Sih eon. 
ose structure, it is to be ote rred that it would undergo rapid decompos!- 
tion in a climate like ours. 
iy 
