EXPLANATION TO PLATE 59. 



Big Moccasin Gap, in Clinch Mountain, Gate City, Va. The crest of the Clinch Mountain 

 represents the present level of the remnant of the Cretaceous peneplain. Duruag Tertiary or 

 Pleistocene times this gap was probably formed l^y the drainage of the Upper Holston system 

 which was then tributary to the Upper Clinch liiver. 

 180 



