BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 13, pp. 139-148 April 21, 1902 



FORMER EXTENT OF THE NEWARK SYSTEM 



BY WILLIAM HERBERT HOBBS 



{Presented before the Society January 2, 1902) 

 CONTENTS 



Page 



Views held by American geologists 139 



Explanation of general acceptance of " local basin " hypothesis 140 



Reconsideration of problem favored by recent monographs 141 



" Local basin " versus " broad terrane " hypothesis — 142 



" Local basin " hypothesis 142 



Marginal faults favor " broad terrane " hypothesis 142 



Attempt to picture Newark conditions of deposition 144 



Coarseness of sediments 144 



Distribution of the conglomerates 145 



Geographic conditions 146 



Conditions favorable to a broad terrane 147 



Views held by American Geologists 



American geologists have quite generally held to the view that the 

 former extent of the Newark system along the Atlantic border was not 

 much greater than at present, the assumption being made that the de- 

 posits were laid down in local basins practically coextensive with the 

 present Newark areas. Russell alone of those who have made special 

 study of the system has advocated a " broad terrane " as against a " local 

 basin " hypothesis for the origin of these deposits.* Davis has expressed 

 the view that the Newark trough of the Connecticut valley was at least 

 8 or 10 miles wider than the present valley ,f but he has thrown the 

 weight of his authority in favor of a strictly " local .basin " of deposition. 

 Shaler and Woodworth in their joint monograph treating of the Rich- 

 mond basin discuss the evidence from that area without reaching a very 



* I. C Russell : On the physical history of the Triassic formation in New Jersey and the Con- 

 necticut valley. Ann. N. Y. Acad. Sci., vol. i, 1879, pp. 220-254. 



See also The Newark system, Bull. 85, U. S. Geological Survey, chap, ix, pp. 101-107. 

 W. M. Davis: The Triassic formation of Connecticut. Eighteenth Ann. Rep. U. S. Geological 

 Survey, 1898, pt. ii, p. 37. 



XXI— Bur.r.. Geoi.. Soc. Am., Vol. 13, 1901 (139) 



