ILLUSTRATIONS 



PtATR Faotng Page 



I. Geological Map of Virginia Coastal Plain in pocket 



II. Fig. 1. Bluff at Dutch Gap, James River, looking upstream. Showing 



Patuxent formation overlain by Pleistocene deposits 63 



Fig. 2. Bluff at Dutch Gap, James River, looking dovi^nstream. Show- 

 ing Patuxent formation overlain by Pleistocene deposits .... 63 



III. Fig. 1. Cut on R. F. & P. R. R. near Cockpit Point. Showing sandy 



beds of Patuxent formation 66 



Fig. 2. Cut on R. F. & P. R. R. near Cockpit Point. Showing sandy 



beds of Patuxent formation 66 



IV. Fig. 1. Bluffs above Widewater on Potomac River. Showing Patapsco 



formation overlain by Pleistocene deposits 68 



Fig. 2. Cut on the R. F. & P. R. R. south of Aquia Creek. Showing 



Patapsco formation overlain by Aquia formation 68 



V. Fig. 1. Base of bluff at mouth of Aquia Creek. Showing zones 2 and 4 



of Aquia formation 94 



Fig. 2. Bluff near mouth of Aquia Creek. Showing blocks of indu- 

 rated marl derived from zone 9 of Aquia formation, largely 



composed of shells of Turritella mortoni 94 



VI. Fig. 1. Bluff at Popes Creek, ^Maryland, Potomac River. Showing 

 zone 17 of Nanjemoy formation oA'erlain by diatomaceous 



earth beds of Calvert formation 107 



Fig. 2. Bluff at Hopyard, Rappahannock River. Showing calcareous 



concretions of Aquia formation 107 



VII. Fig. 1. Nomini Cliffs, Potomac River. Showing Calvert formation... 129 

 Fig. 2. Section 1^2 miles below Bowlers Wharf, Rappahannock River. 



Showing shell marl of St. Mary's formation 129 



VIII. Cliff near Yorktown, York River. Showing indurated calcareous beds 



of the Yorktown formation 161 



IX. Fig. 1. Locality at Richmond showing Lafayette formation overlying 



Calvert formation 1 77 



Fig. 2. Pit at Washington, D. C. Showing Lafayette formation over- 

 lying Calvert formation 177 



X. Fig. 1. Excavation at Richmond. ShoAving Lafayette formation over- 

 lying Aquia formation 178 



Fig. 2. Surface of country at Malvern Hill. Showing Lafayette sur- 

 face 178 



XL Fig. 1. Excavation at Richmond. Showing gravels and loams of the 



Sunderland formation 182 



Fig. 2. Excavation at Washington, D. C. Showing the Wicomico 



formation overlying crystalline rocks 182 



XII. Fig. 1. Wicomico-Talbot escarpment at Fredericksburg 185 



Fig. 2. Talbot Clays at Brick Haven 185 



XIII. Fig. 1. Low bluff 1/2 mile below Bayport Wharf, Rappahannock River. 

 Showing cypress stumps and knees in peat bed of the Talbot 



formation 186 



Fig. 2. Low bluff 1 14 miles above Tappahannock, Rappahannock 

 River. Showing cypress stumps and knees in peat bed of the 

 Talbot formation 186 



