214 WILLIAM H. EMMONS 



ANALYSIS OF VARIETY D. GEO. STEIGER, ANALYST 



SiO, 54-84 H,0- 



Al,03 16.41 H,0+ 



Fe.03 3-63 TiO. 



FeO 4-54 P2O5 



MgO 4-71 BaO 



CaO 6.64 SrO 



Na.O 3-27 Total ^ 



K,0 2.83 



65 



The norm of D is shown in column I of the following table; 

 the mode in column II. 



I. Norm II. Mode 



Quartz 4 . 68 Quartz 6.8 



Orthoclase 16 . 68 Orthoclase 15.4 



Albite 28.30 Albite 27.5 



Anorthite 21 . 41 Anorthite - 19.7 



Hypersthene 11 . 87 Pyroxene 19.5 



Diopside 7.32 Olivine and Serpentine 0.5 



Magnetite S . 34 Biotite 4.6 



Ilmenite i . 98 Magnetite and Ilmenite 5.2 



Apatite i . 01 Apatite 0.8 



Water • ^-^7 Total .100.0 



Total 99.84 



According to the quantitative system, variety D is a monzonose. 

 It is less siliceous than those previously described and is chemically 

 similar to an augite-andesite-porphyry from the Indian Creek 

 laccolith, Yellowstone National Park, described by Mr. Iddings,"" 

 and to a diorite from Mt. Ascutney, Vt., described by Mr. R. A. Daly.^ 



VARIETY E. SHOSHONOSE: ORTHOCLASE-GABBRO 



This variety occurs about a half-mile northeast of the summit of 

 Haystack Peak and a quarter-mile west of Mud Lake, or about 

 halfway between the western shore of this lake and the north spur 

 of Haystack Peak. It is a dark, coarse-grained gabbro in which 

 feldspar, pyroxene, and biotite are visible in hand specimen, the 

 ferromagnesian minerals constituting about one-third of its volume. 



Under the microscope the texture is seen to be hypidiomorphic 

 granular; plagioclase and pyroxene approach idiomorphism ; ortho- 



1 Mon. XXXII, U. S. Geological Survey, p. 83. 



2 Bulletin No. 148, U. S. Geological Survey, p. 69. 



