IGNEOUS AND CRYSTALLINE ROCKS. 97 
K. Same as J, but in altered condition. Also described in 18th Ann. Contains 
sericite, quartz, titanite, apatite, and pyrite, with carbonates of calcium, magnesium, 
and iron. Sp. gr., 2.774, 23° 
Analyses J and K by George Steiger, record No. 1691. 
L. Volcanic sand, Nez Perces region. Collected by I. C. Russell. 
Analysis by W. F. Hillebrand, record No. 1906. 
M. Typical basalt, Cinder Buttes, west side of Snake River plains. Camptonose. 
Analysis by W. F. Hillebrand, record No. 1950. Analysis published by Russell in 
Bull. 199, but the mineralogical composition of the rock is not given. Sp. gr., 2.907 
at 24° 
ri J. K. L M 
65.23 | 66.66] 68.95 51.14 
16.94 | 14.26] 14.33 13. 95 
1. 60 67 1.17 2.15 
1.91 2. 41 1.23 12.97 
1.31 95 47 2.21 
3. 85 3. 37 2.13 6.56 
3.57 | none 5. 08 3.59 
3. 02 4.19 2.58 2. 33 
.18 - 36 28 12 
88 2.16 3. 63 22 
66 49 42 2.41 
ain oie sine SaaeRs - 03 12 
25 Buby. || sis.cjcteeee| Saiaesrenetste, 
19 ot -10 1.59 
trace | trace} trace ~ 44 
gave ese See weven|emes gene trace 
19 | none 08 +25 
edhe cigigcellRxtae seve trace trace 
a fetsiaayci sal asiercsetereee trace none 
none 95 |) EEACO:! |=, -omecrcn 
a -10 
trace 
-15 
trace 
99.78 | 100.11 | 100.48 | 100.30 
MSciecisieis A. a ee Pere ere 
ee lste Seapine! cies sacs MOO: OF 2h icscie:sidsiell ssigatesiaase 
N. Quartz monzonite, near Gem. Pulaskose. Contains plagioclase, alkali feldspar, 
hornblende, and quartz, with a little biotite, pyroxene, titanite, and magnetite. 
QO. Syenite porphyry, near Bradyville. Monzonose. Contains microcline, plagio- 
clase, hornblende, pyroxene, apatite, magnetite, and titanite, with secondary epi- 
dote, sericite, and green amphibole. 
Rocks N, O, from the Cceur d’Alene district, are described by F. L. Ransome and 
F. C. Calkins in P. P. 62. Analyses by Steiger, record No. 2194. 
A 
° 
ro 
ae SESE ite one 
PEE OO RW RDO 
BERRSSSEBRS 
100. 24 99. 83 
COz, ZrOs, and NiO absent. 
