BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 2, pp. 431-450; PL. 16 APRIL 14, 1891 



MESOZOIC AND CENOZOIC FORMATIONS OF EASTERN 

 VIRGINIA AND MARYLAND. 



BY N. H. DARTON, U. S. GEOLOGICAL SURVEY. 



[Read before ihe Society December 30, 1890.) 



CONTENTS. 



Page. 



Introductory . 432 



The Formations _• 433 



The Geologic Column 433 



General Distribution and Structure 434 



Potomac Formation 436 



Distribution 436 



Stratigraphy 436 



The "Albirupean" 436 



Shore Deposits 437 



Stratigraphic Position 437 



Severn Formation 438 



Distribution and Characteristics '. 438 



Stratigraphic Relations and Equivalency 439 



Pamunkey Formation 439 



Distribution and Characteristics 439 



General Features 439 



Nottoway River 440 



Appomattox River 1 440 



James River 440 



Chickahominy River 440 



Pamunkey River 440 



Mattaponi River 440 



Rappahannock River 440 



Potomac River 440 



Patuxent River 441 



Chesapeake Bay 441 



Thickness 442 



Stratigraphic Relations 442 



Taxonomy 443 



Chesapeake Formation — 443 



Distribution and Characteristics 443 



Stratigraphic Relations 444 



Taxonomy 445 



LXTII— Bum,. Geol. Soc. Am., Vol. 2, 180f). (4-51 ) 



