AREAL GEOLOGY OF LOWER CLEAR CREEK 



269 



the Lake Superior, Southern Appalachian, Southern Colorado, and Grand 



Encampment regions. — 



Fundamental Gneiss 

 Wherever in the Clear Creek section the rocks have been studied, this biotite gneiss is 

 found to be -with the Clear Creek Gneiss, the prevailing lithologic unit recognized and 



Gneiss Central City Latite 



Granite Porphyry 

 Scale 



J), 1 2Milas 



Fig. 5. — Idaho Springs and Central City Special^Maps. 



mapped. The Fundamental Gneiss as the prevailing rock is everywhere much phcated 

 and crumbled, and shows signs of having been subjected to intense dynamic metamorph- 

 ism. It is far more metamorphosed than any other rock^of^the country thus far studied. 



