IGNEOUS AND CRYSTALLINE ROCKS. 133 
iy B. CG. D. E. F. 
@ Loss on ignition. 
The following rocks, G to X, inclusive, were collected by J. E. Spurr, who furnishes 
the petrographic data. 
G. Olivine basalt, Crater, Silver Peak. Hessose. Analysis by George Steiger, 
record No. 1883. Contains plagioclase, olivine, and magnetite, in a groundmass of 
feldspar and olivine. 
H. Hornblende-pyroxene-biotite-quartz latite, Coyote Springs, north end of Pahute 
Range. Harzose. Analysis by W. F. Hillebrand, record No. 1881. Phenocrysts of 
hornblende, biotite, plagioclase, quartz, and magnetite, in a brown, glassy groundmass. 
I. Biotite-quartz monzonite, Cherry Creek, Egan Range. Amiatose. Analysis by 
H. W. Stokes, record No. 1882. Contains quartz, biotite, and plagioclase. 
J. Quartz-muscovite rock, Belmont. Described by Spurr in Amer. Jour. Sci., 4th 
ser., vol. 10, p. 358. Analysis by Stokes, No. 1882. Contains quartz and muscovite, 
with some calcite and orthoclase, and a little zircon. P. R. C. 1272. 
K. Hornblende-quartz andesite, Masons Butte, Walker River valley. <Andose. 
Described by Spurr, Jour. Geology, vol. 9, p. 593. Analysis by Stokes, record No. 
1882. Phenocrysts of feldspar, pale-green hornblende (partly altered to calcite, 
chlorite, and epidote), and quartz, in a groundmass of feldspar and hornblende, with 
quartz, pyrite, and siderite. 
L. Hornblende-biotite-quartz diorite, Masons Butte. Tonalose. Described by 
Spurr, as under K. Analysis by Stokes, No. 1882. Contains oligoclase, quartz, horn- 
blende, and biotite. 
G | I. J Kk L 
SiO sacs en aseiee cee seeedeases 47.09 | 62.97 | 67.60] 84.15] 53.37 60. 25 
AkbOs 18.40 | 15.52] 15.89 9.67 | 16.57 17.90 
Fe.03 2. 66 4.03 1.77 51 3. 84 3. 08 
ROO ie sian le ae Ue sss cle omeeiceuinteeteisee Resear Ron 5. 62 1.45 1,82 07 2.45 2.44 
IME O sec cs eadedm sins Aememne aaa eccdeeaetn neacrioos 7.06 2.07 96 04 5.79 2.44 
CaO scterame se reeednmence eevee Se ieee haleeaeoe 10.19 5.31 3.38 53 6. 30 5.57 
NApO exer nome nawminane ees eeenmaies tenes 2. 37 3.31 3.39 2.65 3. 40 4.29 
IK Ovcoarectorsa tele soameracianeulg eeedceceiais Snatemeisids sip ematants 1.34 3. 46 3.39 1.57 2.55 1.89 
SO 8b 105° 2 eis4)crcrys ceneiewinm eins sapere aitianatese cisinavaetenass - 66 - 66 23 21 39 20 
Fiz@ GOVE 1UR at daca uc soe semeas lecdinee sme gemarasts 2. 37 48 87 74 2. 23 1.24 
(OR eascesjossiz cisigaeceancd dinsisiaite pes bs be eee oe 1.19 67 -60 | trace . 86 65 
sein aseteReeS ERS TEAC. arse oa sparai|'s Siavirecaerdll og wedicine Semper 
osteo Sisiay none 1 none | none 1.61 none 
dead wierets 54 -18 19 | trace 25 
mucins aii OS;-|) LACKS |iejece scscasselle Seas ciceopal| Sietacainicee Jaicjeriorsiaie 
crates benirmed| samateeS undet. |......-- OZ a becdeieence| laatemces 
Sistoigiesa ov none -10 | trace} trace 08 06 
Saas SER undet. -02 | trace | trace | trace 07 
Sonne dL .09 | undet, | undet. | undet. | undet. 
sts Seah rae aeaNai abc sbars SiR raed desin Gee Lach ouayrad tanta cis Sis oes Syree iopaaess MEETS tale: |eax nescc}eqese ve |se aewems |ectaniecs 
99. 69 | 100. 50 | 100.09 | 100.16 | 99.73] 100.33 
15619—Bull. 419—10——_10 
