248 Prof. Rogers's Address before the 



England. The larger of the two troughs ranges continuously from be- 

 neath the trap of the Palisadoes of the Hudson southwestward in a 

 diminishing belt to the interior of Virginia, and be3'^ond this point the 

 deposit occurs in narrow detached tracts as far as the southern side of 

 North Carolina. Throughout all this course, the strata dip towards the 

 north and northwest at angles from fifteen to twenty five degrees. The 

 smaller trough fills the valley of the Connecticut river through the 

 whole breadth of Connecticut and Massachusetts, and in this belt the 

 beds dip at an angle of ten or fifteen degrees to the east and southeast 

 and northeast. The materials of both basins are red shale and argilla- 

 ceous sandstone, with some detached beds of conglomerate. 



Of the organic remains, through an investigation of which alone we 

 can hope to establish the position of these strata in the scale of time, or 

 reach definite conclusions respecting the physical conditions under which 

 they were produced, the most instructive are the remarkable bird-tracks 

 bi'ought to light by Professor Hitchcock in Connecticut and Massachu- 

 setts, the fishes of the genera PalfEoniscus and Catopterus, discovered 

 by the Messrs. Redfield in New Jersey and elsewhere, and one or two 

 small but most expressive testacea detected by my brother in the forma- 

 tion in Virginia. Through the discovery by Mr. Redfield of some of the 

 same fishes and even bird-tracks in the two distinct belts described, these 

 deposits are identified in age and origin ; but what exact epoch should be 

 assigned to the formation, was not until lately susceptible of that rigorous 

 demonstration which the present advanced state of our science calls for. 



Guided by mere lithological resemblance, Maclure imagined this stra- 

 tum to be the equivalent of the old red sandstone of England ; but Prof. 

 Hitchcock and Mr. Redfield, chiefly by their investigations into the char- 

 acter of the fishes, have shown conclusively that the date of the deposit 

 is somewhere in the great period of the European new red sandstone, 

 an opinion several years ago expressed by Prof. Hitchcock. But while 

 the low degree of heterocercal structure in the tails of the fishes indi- 

 cated that these strata could not be newer than the new red sandstone, 

 and the same feature and the bird-tracks both proved them newer than 

 the coal, it was still not settled which of the epochs between the oolitic 

 and the carboniferous ones should claim them. The more favorite sup- 

 position was, if I mistake not, that the deposit belonged to the age of 

 the older new red sandstone, and highly instructive as both the fishes and 

 the bird-tracks are, as respects the general date, and above all as regards 

 the nature of the waters, the climate and the surface, still there being 

 among them no one species identifiable with any European relic, some 

 further evidence was required in order to establish the exact epoch. In 



