IGNEOUS AND CRYSTALLINE ROCKS. 99 
\ , 8B. c 
i ee 
56.74 59. 26 59. 29 
18. 80 23. 63 21.27 
15 = 30 3. 33 
6.91 57 1.04 
5.57 31 1.12 
7.34 5.93 5.25 
2.32 4.94 3.39 
77 4.78 3.00 
1.09 .74 1.63 
ADO: shares ecss ad 123 
0% oeseneeere 22 
99. 96 100. 46 99. 76 
SD er eerste cies wishes sae Sea alee seh Ok AE CE oe 2876, 27° 2.625, 31° 2.596, 14. 5° 
2. PIKES PEAK DISTRICT. 
GRANITE. 
Rocks A to G described by E. B. Mathews. For description of A, C, E, and F see 
Jour. Geology, vol. 8, p. 214. Analyses by W. F. Hillebrand, record No. 1470. 
A. Granitite, Sentinel Point, western part of Pikes Peak massif. Alaskose. Con- 
tains microcline, microcline-perthite, quartz, biotite, a little oligoclase, and accessory 
fluorite, apatite, zircon, sphene, magnetite, and allanite. P.R. C. 67 and 600. 
B. Granitite, near road between Florissant and the Platte River. Kallerudose. 
Consists chiefly of microcline in perthitic intergrowth with albite, quartz, and biotite. 
P.R. C. 606. 
C. Porphyritic granitite, south side of Pikes Peak, ridge between Middle and 
North Beaver creeks. Jiparose. Contains microcline, perthite, orthoclase, oligoclase, 
quartz, biotite, and accessory apatite, fluorite, zircon, and magnetite. P. R. C. 602. 
D. Sheared granite, Currant Creek Canyon, north of Twelvemile Park. Jfag- 
deburgose. Contains perthitic microcline, quartz, muscovite, and sericitic aggregates 
replacing plagioclase and a part of the microcline. P. R. C. 604. 
E. Granite, Currant Creek Canyon, north of Twelvemile Park. Omeose. Consists 
chiefly of perthitic microcline, quartz, greenish biotite, muscovite, and plagioclase 
altered to a sericitic mass. Also flakes of limonite. Accessory minerals rare. P. R. 
C. 603. 
F. Granitite, Middle Beaver Creek, south side of Pikes Peak. Liparose. Contains 
microcline, orthoclase, perthitic albite, oligoclase, abundant quartz, biotite, and a 
little accessory magnetite, fluorite, and zircon. P. R. C. 601. 
G. Granite gneiss, north of Twin Creek. allerudose. Contains microcline, ortho- 
clase, quartz, biotite, abundant fluorite, and a little sphene and apatite. P. R. C. 605. 
76 33 «23 89 94 93 
86 1.40 1. 40 - 22 42 97 3.41 
04) trace - 05 207 14 05 31 
80 15 82 - 58 23 Lil 1.23 
os, 14 16 16 15 16 16 16 
H20 above 110 . 30 32 - 66 -92 33 . 62 -31 
TiOg -13 05 .10 312 -07 +18 - 43 
P20; trace | trace - 03 22 -05 | trace 12 
MnO trace -04) trace | trace | trace | trace 15 
Sro. none | none | trace? | none] none | none none 
BaO. trace | trace .03 | trace | trace | trace .14 
THO ps theese: trace | trace | trace | trace | trace | trace -06 
ees 36 12 31 04} none 55 1.00 
CO a snecepaitacieade Sate taeda ek Ree alae eee epee: st 03: | sscencine aceais xc ates seaeles teetas aeceeiecc 
100.55 | 100.23 | 100.25 | 100.36 | 99.75 | 100.38 | 100.59 
Tes8: Ol: 2 aucune sy deegare ey peeaeeies eae teced -0. 13 0: liasstae siete 22 y 
