1912.] NATURAL SCIENCES OF PHILADELPHIA. 373 



AGE AND CORRELATION OF THE "NEW RED" OR NEWARK GROUP IN 



PENNSYLVANIA. 



BY EDGAR T. WHERRY, PH.D. 1 



The so-called "New Red" or Newark group of rocks of the Eastern 

 United States has heretofore been almost universally regarded as a 

 geologic and paleontologic unit, and correlated with the Rhsetic 

 or uppermost Triassic of Europe. Mr. Benj. Smith Lyman, Director 

 of the Mineralogical and Geological Section, who was the first to 

 make a detailed study of any portion of these beds, found them in 

 eastern Pennsylvania to be unexpectedly thick (27,000 feet) and 

 capable of considerable subdivision, and accordingly put forward 

 the suggestion that the group is not all of the same age, but that its 

 deposition began in some portion of the late Paleozoic and con- 

 tinued throughout the Triassic and perhaps even into the Jurassic. 2 

 This view was considered briefly by Ward 3 and cast aside, but the 

 question has never been really settled, and is here reopened and 

 discussed in detail. 



The Paleozoic age of the lowermost beds was inferred by Mr. 

 Lyman from the supposed occurrence of: 



Lepidodendron of Lower Carboniferous type at Newark, N. J. 



Calamites of Permian age at Holicong, Bucks County, Pa. 



Dendrophycus of Devonian aspect at Portland, Conn. 



To which may be added, silicified wood related to Permian species 

 of Europe as described by Knowlton 4 and by the writer. 5 



The identification of the Lepidodendron was made by Lesquereux 

 on a photograph of a poorly preserved fragment, and must therefore 

 at best be regarded as doubtful, even had no other examination of 

 the material ever been made. But Newberry 6 and Fontaine, 7 

 studying the same or a similar specimen, agreed that it represents 

 a conifer, probably Abies or Palissya, while Berry thinks that "all 

 that can be safely said is that it is the decorticated trunk of a gym- 



1 The subject-matter of this paper has been presented in the form of occasional 

 notes at meetings of the Mineralogical and Geological Section of the Academy. 



2 Age of the Newark Brownstone, Proc. Amer. Phil. Soc, XXXIII, pp. 5-10; 

 and Some New Red Horizons, ib., pp. 192-215, 1894. 



3 Status of the Mesozoic Floras of the U. S., Ann. Rept. U. S. Geol. Surv., 

 XX, pt. ii, pp. 218-221, 1900. 



4 Fossil Wood and Lignite of the Potomac [and Newark] Formation, Bull. 

 U. S. Geol. Surv., No. 56, p. 52, 1889. 



5 Preceding paper. 



6 Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the 

 Connecticut Valley, Mon. U. S. Geol. Surv., XIV, pp. 94, 95, 1888. 



7 In Ward's Status of the Mesozoic Floras of the U. S., Ann. Rept. U. S. Geol. 

 Surv., XX, pt. ii, p. 219, 1900. 



