106 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
K. Dacite, Bald Mountain, near Rosita. Lassenose. Contains plagioclase, biotite, 
hornblende, sometimes augite, magnetite, and quartz. Sp. gr., 2.574, 24°. Record 
No. 1068. P. R. C. 530. 
L. Mica dacite. Lassenose. Contains plagioclase, sanidine, biotite, and quartz. 
Sp. er., 2.563, 24° Record No. 1068. 
M. Rhyolite, Pennsylvania Hill. Toscanose. Sp. gr., 2.470, 26°. Record No. 
1079. P.R. C. 525. 
N. Rhyolite, Round Mountain. Omeose. Contains sanidine, quartz, some glass, 
and accessory garnet. P.R.C. 521. x 
O. Rhyolite, Silver Cliff. Magdeburgose. Sp. gr., 2,560, 15° Record No. 1125, 
P.R. C. 522. 
P. Rhyolitic tuff, a lake-bed deposit east of the Blue Mountains. Mainly com- 
posed of glassy rhyolite dust. 
Q. Devitrified pitchstone, the gangue of ptilolite, 3 miles southeast of Silver Cliff. 
Riesenose. Shows feldspar, quartz, and barite. Described by Cross and Eakins in 
Am. Jour. Sci., 3d ser., vol. 44,,p. 96. Record No. 1342. P. R. C. 590. 
R. Pitchstone, Rosita. Alaskose. Record No. 1033. P. R. C. 531. 
8. Pitchstone, Fleetwood tunnel, Silver Cliff. Liparose. P. R. C. 523. 
T. Alteration product of 8S. Consists mainly of silica and kaolin. Record No. of 
Sand T 1034. P. R. C. 591. 
U. Decomposition product of pitchstone, Silver Cliff. Analysis by W. F. Hille- 
brand. 
V. Syenite, Silver Cliff. Monzonose. Contains orthoclase and plagioclase in 
nearly equal amounts, colored by ferric hydroxide, with amphibole, a little biotite, 
and secondary epidote, calcite, and chlorite. Sp. gr., 2.689, 20°. P. R. €. 71 
and 520. 
