IGNEOUS AND CRYSTALLINE ROCKS, 1138 
10. SILVERTON QUADRANGLE. 
Rocks A, B, C, D described by Whitman Cross in Folio 120. Analyses by W. F. 
Hillebrand, record Nos. 2024, 2042, 2045. 
A. Quartz latite, ridge north of Pole Creek. Amiatose near yellowstonose. Contains 
phenocrysts of andesine, hornblende, and a little biotite, in a predominant groundmass 
of orthoclase, plagioclase, quartz, and a little augite, biotite, and magnetite. P.R.C. 
1353. 
B. Quartz latite, bench south of Greenhalgh Mountain. Toscanose. Contains 
phenocrysts of oligoclase-andesine and biotite in a groundmass of orthoclase, quartz, 
and rare accessories. P. R. C. 1354. 
C. Pyroxene andesite, ridge west from Edith Mountain. Tonalose. Contains 
phenocrysts of labradorite, augite, hypersthene, biotite, and magnetite, in a ground- 
mass which is largely glass, with feldspar microlites and ferritic particles. P. R. C. 
1355. 
D. Pyroxene andesite, Dolly Varden mine, Henson Creek. Harzose. Contains 
phenocrysts of labradorite, hypersthene, augite, and magnetite, in a groundmass of 
plagioclase, orthoclase, quartz, augite, magnetite, etc. P. R. C. 1356. 
| 
A | Be |. &. » D 
62.09 | 64.93 | 58.88 56. 03 
16.77 | 16.79 | 15.93 15. 97 
3.9 3. 54 3.12 4.78 
99 82 2.94 3.00 
1.63 65 2. 30 3. 36 
4. 26 2.11 6.05 6.44 
3.77 3.33 3.17 2.85 
K:0... 3. 68 4.76 1.86 3.29 
gO 8 at LOS? oe2 orescence eee anans sea manirnee Meenas Cam OAR a Soa - 50 1.12 1. 66 1.31 
gO ADO VO 10D sas. ausscistarciescicasictn ara cnenieretoinisinietishtncnnasieceaRelannare Ree 1.32 1.65 2. 48 1.08 
Di Ofvereiean su niu dine tivieece mea wee arconeon damaseahuias ipeincnout nats weaeRis .73 - 53 -73 1.01 
ZU O9: gesscn sweets Seema te tence da da AEE A eRe wea eae trace 03 -02 | trace? 
IPO bieyoc,narnie aiscncpn nn aaamciiae s meueade aT aes SORE E Nee +25 olf 34 - 48 
nO 14/ trave -16 16 
BaO. 10 -15 22 08 
$rO. 05 | trace 14 04 
LizO . trace | trace |) trace |........ 
iw st genrateeislereis cisrnaustaveyatsicinasiassjoimns isis argereaiercle tierra ae none | trace? |.....-.- none 
POSaswewsaannra tance euusmainswateaeaint ced au nareie aun siaciyecieeees to oieie netarmacra Semetepctos | emkeassisces OF Jasessses 
100. 24 | 100.08 | 99.97 99. 88 
COaabsent. Cl, F, not looked for. 
Rocks E to I described by F. L. Ransome in Bull. 182. 
E. Altered andesitic breccia, White Cloud mine. Contains quartz, kaolin, pyrite, 
rutile, and some undeterminable minerals. Analysis by George Steiger, record No. 
1886. 
F. Latite, country rock, Polar Star mine, Engineer Mountain. SR. 3 of vaalase. 
Contains labradorite, orthoclase (?), quartz, diopside, chlorite, calcite, serpentine, 
kaolin, magnetite, hematite, apatite, rutile, and leucoxene. Mainly feldspar and 
quartz. 
G. Altered latite, same locality as P, wall rock of vein. Contains mainly quartz 
and kaolin, with diaspore, pyrite, sericite, rutile, and apatite. 
H. Monzonitic porphyry, near Yankee Girl mine. Adamellose. Contains albite, 
quartz, orthoclase, chlorite, calcite, sericite, iron ores, pyrite, and apatite. 
I. Altered monzonitic porphyry, near National Belle mine. Contains quartz, 
kaolin, pyrite, diaspore, sericite, apatite, and rutile. 
Analyses F to I by H. N. Stokes, record No. 1888. 
