No. l8.] TRIASSIC FISHES OF CONNECTICUT. 



23 



II. 



GEOLOGIC CORRELATION OF THE CONNECTICUT 

 VALLEY FISH-BEARING BEDS. 



The general consensus of opinion among geologists who have 

 studied the Triassic rocks of eastern North America is that the 

 sediments were deposited more or less contemporaneously^ in a 

 number of isolated basins or troughs, these depressions occurring 

 at intervals (rather than extending continuously) along the 

 Atlantic border from Nova Scotia to South Carolina. As to the 

 period of deposition represented by these sediments, in the opinion 

 of the best authorities they are referred to the uppermost division 

 of the Triassic system, that which in European geology is termed 

 the Keuper. This opinion, be it observed, has rested hitherto al- 

 most exclusively upon the evidence of paleobotany. And not un- 

 naturally, owing to the prevailing dearth of marine invertebrates, 

 which always afford the most reliable indication of the age of 

 strata. 



In view of the almost total absence of the latter class of 

 fossils, it is pointed out by Professors Rice and Gregory in their 

 " Manual of the Geology of Connecticut" (p. 182), that the best 

 paleontological evidence for purposes of correlation which is 

 here available is that " afforded by comparison of the fossil 

 plants, which occur abundantly in some areas of the formation, 

 particularly in the Richmond area, with the fossil plants of some 

 of the European strata." The results of such comparison show, 

 as stated by these authors, "that the flora of these sandstones 

 finds its nearest equivalent in that of the Keuper, the uppermost 

 division of the European Trias. The indications afforded by the 

 fishes and reptiles, though more scanty, are in harmony, so far 

 as they go, with the evidence of the plants." In like manner 

 Professor Lester F. Ward, writing in 1891, expressed the view 

 that the flora of the New York- Virginia area fixes the horizon 

 of the so-called " Newark formation " " with almost absolute 



