CENOZOIC HISTORY. 



585 



later Columbia waters do not appear to have extended beyond 

 the Falls. 



In the James river valley the Pleistocene submergence was 

 continuous below Richmond. Either the earlier Columbia or 

 later Columbia waters, or the continuous Pleistocene submergence 



Figure 5. Map of the Middle Atlantic Slope, indicating the conditions in the time 

 of Post-Columbia maximum uplift. There is also shown on the map the nature of the 

 deformation of the Tertiary peneplain in 100 foot contours; and the present extent of 

 Lafayette deposits. 



may have extended far westward. Mr. Keith informs me that 

 there is a succession of gravel-capped terraces along the valley 

 in the Lynchburg region, and these may represent Lafayette, 

 earlier Columbia, and later Columbia deposits, laid down in 

 succession during oscillations in a general uplift, as in the 



