SMITHSONIAN INSTITUTION 



Fig. 19. — Clinch sandstone on south side of Clinch Mountain, south of 

 Eidson, Tenn. This resistant sandstone forms the backbone of this long 

 mountain. 



.****' 





*g 



Fig. 20. — Black River limestone at Chattanooga, Tenn. The man on the 

 right is standing on a soft bed of volcanic ash or bentonite, which indicates 

 presence of active volcanoes in Ordovician time. Photograph by J. Bridge. 



