SANDSTONE DIKES 



ACCOMPANYING THE GREAT FAULT 



OF UTE PASS, COLORADO. 



BY W. O. CROSBY 



introduction- 

 Three years aijo, Whitman Cross' first directed the 

 attention of geoloffists to the fact that dike-like masses 

 of sandstone occur in the granite of the Pike's Peak 

 massif, formino^ a belt aliout one mile wide extending 

 north-northwest from the vicinity of Green Mountain 

 Falls, in Ute Pass, along the southwest side of the 

 narrow Manitou Park l)asin of sedimentary rocks (Silu- 

 rian and Carboniferous). Among the most important 

 characteristics of the dikes noted by Cross are the fol- 

 lowing : — 



L The dikes have a general trend parallel to the l)elt 

 in which they occur ; are approximately vertical and 

 often appear as a complex of nearly parallel fissures with 

 many In-anches and connecting arms ; and vary in width 

 from mere tilms to two or three hundred yards, the 

 largest being a mile or more in length, and forming 

 ruffffed ridsres with narrow crests which contrast mark- 

 edly with the gently sloping hills of granite alwut them. 

 In short, ''in all formal relationships to the enclosing 



' Bull. Geol. Soc. Aincrica, .'>, 225-2;;0; 

 U. S. Geol. Survev, I'ike's Teak Folio. 



(113) 



