84 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
D. Syenite, Wright and Edwards mine, Hughesville, near Barker. Toscanose. 
Very fresh rock. Contains magnetite, ilmenite, hornblende, anorthoclase, albite, 
subordinate quartz, a little chlorite, calcite, and limonite, and white mica in traces. 
Analysis by Stokes. P. R. 0. 1477. 
E. Syenite, Yogo Peak. Monzonose. Described in Am. Jour. Sci., 3d ser., vol. 50, 
p. 471. Contains apatite, sphene, iron ore, pyroxene, hornblende, biotite, orthoclase, 
oligoclase, and quartz, with traces of chlorite and limonite and a little kaolin. Analy- 
sis by Hillebrand. P. R. C. 1478. 
F. Granite porphyry, dike at head of Sheep Creek. Toscanose. Phenocrysts 
of orthoclase, some plagioclase, and green hornblende, in a groundmass of alkali 
feldspar, with some quartz. Also contains a little apatite and iron ore, with some 
secondary calcite and kaolin. Analysis by Hillebrand. P. R. C. 1479. 
A B ie Dz. E F 
SiO Go. 50 ccccc secede reeems ae beemiocemeerpes deca 73.12 | 69.68 | 68.60] 64.64] 61.65 66. 29 
ANIO3 222 ceceeeveeceax ses vavecmeereeeees teremedeesen ess 14.27 | 14.97) 16.13] 16.27 | 15.07 15.09 
Fe203 51 79 2. 22 2. 42 2.03 1.37 
FeO. 26 34 -44 1.58 2.25 1.17 
MgO 24 66 +72 1.27 3. 67 2.39 
CaO. 1.10 2.10 1.36 2. 65 4.61 2. 38 
INO crea acti cowcabep tele cies aus Mibeoin Unerasaeeaeee 3. 43 3. 38 4.37 4.39 4.35 3.96 
NRG Oo ds Sosa denies a eeeae ace aie Dae een aseERS 4.90 4. 40 4.89 4,98 4.50 4.91 
BO at M0). we ceieciss sas cicmemainemacisers tesaniemanvecas - 68 1.09 - 20 -09 - 26 -39 
H20 above 110° a 73 92 - 58 27 41 - 60 
i = 08 28 32 51 56 +27 
G. Syenite porphyry, intrusive sheet, between Yogo Peak and Big Baldy Mountain. 
Lassenose. Abundant phenocrysts of hornblende and orthoclase, with less biotite 
and plagioclase, in a groundmass of alkali feldspar with accessory quartz. Also con- 
tains iron ore and apatite, with secondary calcite, chlorite, sericite, and kaolin. 
Analysis by Hillebrand. P. R. ©. 1480. 
H. Granite porphyry, north end of Thunder Mountain. Toscanose. Phenocrysts 
of orthoclase, oligoclase, hornblende, and biotite, in a groundmass of alkali feldspar 
and very abundant quartz. Also contains a little sphene, iron ore, and apatite, very 
little secondary chlorite and limonite, and a trace of kaolin. Analysis by Stokes. 
P. R. C. 1481. 
I. Granite porphyry, top of Big Baldy Mountain. Toscanose. Phenocrysts of 
orthoclase, plagioclase, biotite, iron ore, brown hornblende, and sphene, in a ground- 
mass of quartz and alkali feldspar. Also contains a little apatite, with traces of 
chlorite, limonite, and kaolin. Analysis by Hillebrand. P. R. C. 1482. 
J. Quartz monzonite, talus slope on west side of Bear Park. Dacose. Phenocrysts 
of biotite, hornblende, plagioclase, and orthoclase, in a groundmass of quartz and 
alkali feldspar. Also contains a little magnetite, chlorite, white mica, and apatite. 
Analysis by Stokes. P. R. C. 1483. 
K. Diorite porphyry, Steamboat Mountain. Adamellose. Phenocrysts of orthoclase, 
plagioclase, hornblende, and biotite, with a little iron ore and apatite, in a ground- 
mass of orthoclase, plagioclase, and quartz. Analysis by Stokes. P. R. C. 1484. 
L. Diorite, Carpenter Creek, near Neihart. Andose. Contains green hornblende, 
biotite, and plagioclase, with some apatite, iron ore, calcite, kaolin, and muscovite, 
and a very little quartz and orthoclase. Analysis by Hillebrand. P.R. C. 1485. 
