"206 WATSON AND CLINE ROCKS OF THE BLUE RIDGE REGION 



I. Quartz nionzonite from Hailey, Idaho. W. F. Hillebrand, analyst. W. 



Lindgren : Twentieth Annual Report, United States Geological Survey, 



1900, part iii, page 91. 



II. Quartz monzonite, near San Miguel Peak, Telluride, Colorado. H. N. 



Stokes, analyst. W. Cross : Telluride Folio, United States Geological 



Survey, 1899, page 6. 



III. Quartz monzonite, Nevada Falls Trail, Yosemite Valley, California. W. 



Valentine, analyst. H. W. Turner : Journal of Geology, volume vii, 

 1899, page 152. 



IV. Granite (quartz monzonite), Walkerville Station, Butte, Montana. H. N. 



Stokes, analyst. W. H. Weed : Journal of Geology, volume vii, 1899, 

 page 739. 

 V. Average quartz monzonite, twenty analyses averaged. R. A. Daly : Igne- 

 ous rocks and their origin, 1914, page 386. 



Norms corresponding to Analyses of Quartz Monzonite on page 205 



I II III IV V 



Q 25.1 22.2 19.1 19.3 22.98 



Or 25.6 26.7 27.2 25.0 22.24 



Ab 26.7 26.2 30.4 23.6 29.34 



An 13.1 14.2 12.1 18.1 16.68 



C .3 .... .4 . ..'. ..... 



Di 2.6 .... 1.3 



Hy 5.0 3.4 4.1 6.7 4.95 



Mt. 1.4 3.9 3.5 4.2 2.78 



II 9 1.1 1.4 .91 



Ap .31 



Normative Feldspar Composition 



I II III IV V 



Total plagioclase 39.8 42.5 40.4 41.7 46.02 



Total feldspar 65.3 69.7 67.1 66.7 68.26 



Ab n An m 2:1 2.5:1 1.8:1 1.3:1 1.8:1 



Orthoclase-plagioclase ratio ... 1 to 1 . 5 1 to 1 . 6 1 to 1 . 5 1 to 1 . 7 1 to 2 . 1 



COMPARISON WITH AKERITE " 



In 1914, Phalen 15 applied the name hypersthene akerite to the rock 

 from Milams Gap, in Page and Madison counties, Virginia, because of 



14 The name akerite was proposed by Brogger (Zeitsch. f. Kryst., vol. xvi, 1890, p. 43) 

 for a variety of syenite at Aker, Norway, consisting of orthoclase, niuch plagioclase, 

 biotite, augite, and some quartz. Rocks referred to this type have been described as 

 plagioclase-augite syenite, whose feldspars are soda microcline and lime-soda feldspar. 

 According to Iddings (Igneous rocks, vol. ii, 1913, p. 164), they may also be classed as 



, soda monzonites. The akerites show wide variation ir. composition and belong to differ- 

 ent groups. 



15 W. C. Phalen : A new occurrence of unakite — a preliminary paper. Smithsonian 

 Miscellaneous Collections, vol. 45, 1904, p. 311. 



