Palcontologic and lithologic analysis of several gravel zones within the Nanscmoncl Formation provides new information for the interpretation of the gcomorphic and palcogeographic history of the James River drainage basin. A basal gravel zone, containing pebbles and cobbles of rock characteristic of the Bine Ridge and Piedmont, suggests that the James River had not extended its drainage basin beyond this area by the beginning of Nanscmond time. An upper gravel zone, containing lossiliferous chert and limestone fragments predominantly of Devonian age, suggests that the James River system did not reach the Devonian source area in the Valley and Ridge Province until late Nanscmoncl time.

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