44 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
Cl and F not looked for. 
R. Grorudite, about 2 miles north of the summit of Chisos Mountain. Grorudose- 
pantellerose. Contains alkali feldspars and subordinate quartz, with riebeckite and 
eegirite in irregular interstitial patches. Sp. gr., 2.648, 15.5°. 
S. Pulaskite, Santiago Mountain. Nordmarkose. Consists of alkali feldspars, with 
subordinate egirite, xgirite-augite, riebeckite, magnetite, and rare lovenite. Sp. 
gr., 2.581, 25.59. 
T. Syenite porphyry, Iron Mountain, near Marathon. Nordmarkose. Contains 
many oligoclase-albite phenocrysts in a groundmass of alkali feldspar, with very little 
quartz. Titanite, apatite, and magnetite are present in small amounts. Sp. gr., 
2.577, 15.5°. 
U. Essexite, Big Hill Canyon, Rio Grande. ssexose. Contains predominant 
orthoclase, soda-rich plagioclase, and nephelite, with considerable augite, olivine, 
and magnetite, and small amounts of biotite and apatite. Sp. gr., 2.686, 25.5° 
V. Syenite porphyry, Hueco Tanks, El Paso County. Phlegrose near nordmarkose. 
Collected and described by G. B. Richardson. Contains orthoclase, albite, oligoclase, 
biotite, augite, quartz, ilmenite, magnetite, and apatite. Analysis by G. Steiger, 
record No. 2162. 
