THE TRIASSIC PERIOD 683 



Structure. The structure of the Newark series is generally 

 monoclinal. In the Connecticut River valley the dip is about 20 

 (10 to 25) to the eastward. In the New York- Virginia area l also 

 the structure is monoclinal, the dip being to the northwest (10-15). 

 This contrast of dips between the New England and New Jersey 

 areas -has been thought to support the suggestion that the strata 

 of the two areas are parts of one huge anticline, from the broad crest 

 of which the beds have been removed. The strata are otherwise 

 somewhat deformed, though never closely folded. The series is 

 faulted extensively, and in a somewhat complicated manner. 



Thickness. On account of the faulting, the thickness of the 

 Newark series is difficult of determination. In the Richmond area 



TUCKAHOE CffEt( 



Fig. 467. Structure of the Newark series on the James River, Richmond 

 area, Va. A A, minor flexures; ff, faults. Structure of the deeper 

 parts hypothetical. The heavy black band represents coal. (Shaler 

 and Woodworth, U. S. Geol. Surv.) 



of Virginia, it is estimated at something more than 3,000 feet; in 

 New England, at 7,000 to 10,000 feet; and in New Jersey even more. 

 Correlation. The stratigraphic relations of the Newark series in 

 the United States would not determine its age. It lies unconfor- 

 mably on rock which is mainly pre-Cambrian, and is overlain un- 

 conformably by Comanchean (Lower Cretaceous) beds. About 

 the Bay of Fundy, however, the rocks lie unconformably on the 

 early Permian. The physical relations of the Newark series 

 therefore show that it is post-early-Permian, and pre-Comanchean. 

 Between the Permian and the Comanchean there are two periods, 

 the Triassic and the Jurassic. In referring the series to the former, 

 the chief reliance is on the fossils, and on the same basis it is believed 

 to represent only the later part of the period. 2 



1 For summary of the Newark of New York and New Jersey, see Kiimmel, 

 Kept, of the State Geologist of New Jersey, 1896, and Jour. Geol., Vol. VII. 



2 Rice and Gregory would make the Newark the approximate equivalent 

 of the Keuper of Europe. Bull. 6, State Geol. and Nat. Hist. Surv. of Conn. 



