BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 13, PP. 187-214, PLS. 22-28 JULY 29, 1902 



GEOLOGY OF THE POTOMAC GROUP IN THE MIDDLE 

 ATLANTIC SLOPE 



BY W. B. CLARK AND A. BIBBINS 



{Presented before the Society December 31, 1901) 

 CONTENTS 



Page 



Introduction 188 



Descriptions of the constituent formations of the Potomac group in Maryland 190 



The formations and their relations 190 



Patuxent formation 191 



Name and lithologic characters , 191 



Organic remains , 192 



Strike, dip, and thickness 192 



Areal distribution and boundaries 193 



The Algonkian- Patuxent boundary 193 



Characteristic local section , 194 



Economic products 194 



Arundel formation 194 



Name and lithologic characters 1 94 



Organic remains . , 195 



Strike, dip, and thickness 195 



The Patuxent-Arundel boundary 196 



Areal distribution 197 



Characteristic local section 197 



Economic products 197 



Patapsco formation 198 



Name and lithologic characters 198 



Organic remains 199 



Strike, dip, and thickness 199 



The Arundel-Patapsco boundary 199 



Areal distribution 200 



Characteristic local section 200 



Economic products 200 



Raritan formation 201 



Name and lithologic characters 201 



Strike, dip, and thickness 202 



Organic remains 203 



The Patapsco-Raritan and Raritan-Matawan boundaries 203 



Areal distribution 203 



XXVIII— Bui,r,. Geot,. Soc. Am., Vol. 13, 1901 (187) 



