28 PROCEEDINGS OF THE ACADEMY OF [Part I 



and in another friable and soft. The color may be red or green. 

 Its content of silica, clay, feldspar and mica varies. 



Historical Geology. 



In general, geologists now regard the theory of continental origin 

 of the beds of the Newark System as definitely proven. ^ ^ ^^^ 



From the floral remains the triassic rocks of York County are 

 placed by Fontaine in the Upper Trias and correlated with the 

 Rhetic of Bavaria." Lull, from the faunal remains of the Con- 

 necticut valley, states that ''the Newark System may bridge the 

 time between the Triassic and Jurassic. "^^ 



The presence of at least five different fresh-water mollusca in 

 the York County Trias is indicative of fresh rather than saline- 

 water conditions. The carbonaceous black shale containing the 

 fish scales and fossil plants proves the presence of luxuriant vege- 

 tation in swamps, or lakes. This conclusion is still further verified 

 by the occurrence of thin coal lenses and numerous casts of limbs. ^^ 



CRUSTACEANS. , 



The shells of two species of small crustaceans are found closely 

 associated in the black shales. These were identified as Candona 

 rogersi (Lea) and Estheria ovata (Jones). ^^ The former are found more 

 abundantly and often cover the surface of the matrix in densely 

 crowded masses. Localities: Carbonaceous shale. Little Cone- 

 wago (loc. 3); Black shale, York Haven (loc. 4). 



FISHES. 



The great variety of fish scales (Plate I, figs. 1-17) warrants their 

 presentation. Some of the specimens are sufficiently different from 

 known forms to indicate the presence of new species. The scales 



« Russell, I. C. The Newark System. U. S. Geol. Survey, Bull. 85, Chapter 

 V, 1892. 



' Davis, W. M. The Triassic formation of Connecticut. U. S. Geol. Survey, 

 18th Ann. Rept., pp. 32-34, 1898. 



^^ Barrell, .J. Relations between climatic and terrestrial deposits. Jour. 

 Geol., vol. XVI, pp. 182, 259, 1908. 



1^ Ward, L. F. Status of the Mesozoic floras of the United States. U. S. 

 Geol. Survey, 20th Ann. Rept., p. 255, 1898-99. 



'2 Lull, R. S. Triassic life of the Connecticut Valley. Geol. and Nat. Hist. 

 Survey of Conn., Bull. 24, p. 20, 1915. 



13 Wherry, E. Silicified wood from the Trias of Pennsylvania. Acad. Nat. 

 Sci. Proc, Phila., 1912. 



" Jones, T. R. A monograph of fossil Estheriae. Palaeontographical Soc, 

 pp. 84, 124, London, 1862. 



