732 



JOHN W. GRUNER 



On the east of the Taos Range the broad Moreno Valley 

 separates the Taos Range from the Cimarron Range, which is 

 nearly as high. On this eastern slope of the range watercourses 

 are rather scarce. 



.w^J"^"''" i COUNTY 



36* 



lob" 



io^o 



Scale I :r, 000,000 



Fig. I.— North central New Mexico showing location of area mapped. Copied 

 from Plate I of Professional Paper No. 68. 



DESCRIPTIVE GEOLOGY 



The Taos Range is built up of three great rock systems. The 

 pre-Cambrian gneisses, schists, and granites constitute the basement 

 and greater part of the core of the uplift. Upper Carboniferous 

 strata of great thickness are turned up on the east and south sides 

 of the range. These older systems are intruded by stocks and dikes 

 of granite and rhyolite porphyry respectively. 



Along the western slope of the mountains large alluvial fans 

 spread over the plains toward the Rio Grande for a number of miles, 



