Address before the Association of American Geologists. 245 
tity. Besides, in all of them we find limestones of a similar cha- 
racter, extensive ridges and dykes of greenstone, and ores of cop- 
pér, associated with the sandstones and shales ;—so that there can 
hardly” ‘remain a doubt as to the identity in age of ‘all these de- 
posits. But’can we determine their true place on the wise 
scale ? 
_ The Professors Rogers, who have extensively examined this for- 
mation in the middle states, have ascertained that it is more re- 
cent than the coal measures; and with commendable caution, 
they have called it the middle secondary. With less of pru- 
nee Llong since ventured to denominate it the new red sand- 
stone ;—and I hope it is not prejudice which makes the argument 
in favor of this opinion appear to be now almost complete. A 
careful comparison of numerous specimens of this formation with 
a series from the new red sandstone of continental Europe, and 
Great Britain, shows a striking resemblance in lithological cha- 
racters.. But the argument { from the organic: remains is the most 
decisive. formatio pecially in New Eng- 
land and New Jersey, have*been:-found.-namerous sépeoieens:of 
fossil fishes of the genera Paleoniscus’ ore egy all of 
which have heterocereal tails Now in Europe, Prof. Agassiz 
finds that such fish rarely, if ever, occur in any rock above the 
new red sandstone. But in that formation he finds not less than 
a dozen species of the genera just mentioned. » They occur, how- 
ever, in the coal formations, beneath the red sandstone. But it 
seems to be admitted on all hands, that the group in our country 
under consideration, is more recent than the coal measures. And 
since the heterocercal fishes found in it show that it must be - 
older than the lias, I see no escape from the ‘conclusion that it is 
the new red sandstone. There are other arguments to the same 
point; but they are less decisive. Whether we shall find all the 
subdivisions of this formation in our country that exist in Ea- 
rope, ‘remains to be seen. I have little doubt, however, that 
several of them may be easily recognized ; as, for example, the 
ar marls and sandstone, the new red conglomerate, (Rothe 
— ) and the: zechstein. 
ho have 
informed by Messrs. Redfield, the father and the son, W 
maa devoted themselves | to an examination of our dee fishes, that they. have 
= 
. oo is 
a> bd 
