742 JOHN W. GRUNER 



A more difficult problem arises from the question when deposi- 

 tion of sediments ceased. Stevenson speaks of the Jura Trias 

 "Red Beds" that occur farther east and south as resting conform- 

 ably upon the Carboniferous/ Lee, on the other hand, would 

 rather assign them, at least partly, to the Pennsylvanian system,^ 

 He also favors the assumption that during Cretaceous time the 

 sea covered practically all of the territory now occupied by the 

 southern Rocky Mountains.^ Until further evidence is found to 

 prove that this view is correct, the present writer is inclined to 

 believe that the site of the Taos Range proper during the Cretaceous 

 was not, or only for a short epoch, an area of deposition for the 

 reason that no Cretaceous sediments have been discovered on the 

 west side of the Culebra and Mora ranges as far as can be learned 

 from the available literature. 



Probably during early Tertiary, deep-seated intrusive activity 

 resulted in the uplift of the Sangre de Cristo Range. Since that 

 time erosion has been at work continually. Glaciation in recent 

 time has been an especially powerful agent in the process of 

 destruction of the mountains. 



ECONOMIC GEOLOGY 



It is not likely that this district will ever attain great importance 

 on account of its mineral resources. Three deserted camps on the 

 Rio Hondo tell of an attempt to extract gold at South Fork and 

 Almozzet, and copper at Twining. Lindgren has described these 

 occurrences."* 



A number of short prospect tunnels are situated in and close 

 to some of the rhyolite dikes near Fairview Mountain and Lucero 

 Peak where pyritization has altered the schist. Another claim is 

 at the head of Elm Creek, near the base of the Pennsylvanian, where 

 a narrow vein of barite and galena outcrops in the sediments. 



' Op. cit., p. 85. 



2 Op. cit., p. 39. 



3W. T. Lee, "Relation of the Cretaceous Formations to the Rocky Mountains 

 in Colorado and New Mexico," U.S. Geol. Survey Prof. Paper g6 (1916), p. 40. 



-i W. Lindgren and L. C. Graton, "The Ore Deposits of New Mexico," U.S. Geol. 

 Survey Prof. Paper 68 (19 10), p. 83. 



