294 
GEOLOGY OF THE FIRST DISTRICT. 
Durham and Southbury in Connecticut; and of Morris county, New-Jersey, belong to that 
division of Agassiz’s classification, which he calls Heterocerci; that is, having tails with un¬ 
equal lobes, and called unsymmetrical or heterocercal. In these the scales, and probably the 
vertebrae, extended to the extremity of the upper lobe. Such fish have been found rarely, if 
at all, in any formation above the new red sandstone. Hence, then, any rock containing them 
in Massachusetts, Connecticut and New-Jersey,” (and he might have added New-York,) 
“ must be as old as the new red sandstone,”* 
The position occupied by the red sandstone under consideration, may be considered then to 
be that of the new red sandstone, as it is above the coal, below the greensand, and below those 
beds called the potter’s clay; which, if we have any beds equivalent to the lias and oolite, 
would occupy their position. Many collateral evidences are adduced by Prof. Hitchcock 
which are not decisive, but afford presumptive evidence tending to the same conclusion. The 
principal of these are, first, lithological characters; secondly, the bones of vertebrata that 
were not fishes, and found in the sandstone; and thirdly, the tracks of birds and animals 
found on the sandstone in quarrying.! t 
Prof. Hitchcock was considered years ago as having almost demonstrated the equivalency 
of the red sandstone of the Connecticut valley, to the new red sandstone. There can be 
scarcely a doubt, that the red sandstone east of the Blue ridge and Highlands ; that of the 
Connecticut, and of the Housatonic valleys ; and doubtless those of Lake Superior, the Rocky 
mountains, and Nova-Scotia, are identical in age, as they are in their general characters and 
in their associated rocks and minerals, and in their fossils so far as we know. The more 
recent observations of Prof, H., those of Professors Rodgers in Virginia, Pennsylvania and 
New-Jersey, and my own in New-York, afford additional evidence tending to the same con¬ 
clusion. 
* Prof. Hitchcock’s Geological Report of Massachusetts, 1840, p. 438. 
t I have seen no tracks on the red sandstone of Rockland and Richmond counties, but they may very possibly be found 
there, My researches were necessarily very limited, in examining this, and in fact all the regions explored in New-York. 
The law required the surveys to be made in a fixed time ; and to satisfy public opinion, equal times were devoted to ex¬ 
ploring equal areas. The consequence is, that scarcely more than a reconnoisance has been made of any part; and the 
most interesting fields for geological research had scarcely begun to open their treasures of facts, before they were left for 
new fields of labor. 
11 have numerous specimens of the fishes from this formation in Connecticut, where I have dug out hundreds of them. 
Those at Durham are in a bituminous calcareous slate, and the animal matter is changed to bituminous coal. The fol¬ 
lowing section shows the position of the fishes : 
1. Drift and gravel beds. 
2. Red sandstone. 
3. Red and grey crumbling sandstone (very fissile). 
4. Calcareous slate containing ichthyolites. 
5. Sandstone and slate (fissile), 
6. Shale, 
