IGNEOUS ROCKS FROM THE ORTIZ MOUNTAINS 233 



Shoshonose-Monzonose-Akerose-Andose. II. 5. 2-3. 3-4. 



(Diorite) 



This rock is gray, fine-grained, and holocrystalline. It is not 

 porphyritic. The specimen from which the analysis was made is 

 from a spur of about 7,500 feet in altitude on the southeastern side 

 of the group. 



Chemically the type is remarkable in being exactly on the division 

 line between rangs 2 and 3, and nearly so between subrangs 3 and 

 4. Hence the complex name. 



Microscopically it contains orthoclase, two plagioclases, augite, 

 a green pleochroic hornblende, titanite, magnetite, apatite, and a 

 small amount of nepheline. 



TABLE IV 



Chemical Composition of Shoshonose-Monzonose-Akerose-Andose 



Akerose. II. 5. 2. 4 (Diorite) 



The type is essentially similar to the last, except that its color is 

 pinker in tone, due to the presence of considerable red orthoclase. 

 No nepheline is present, but there is a small amount of quartz. It 

 forms the mountain 8,200 feet high on the southeastern side of the 

 group. 



