ITHACA GROUP. 
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The rock at Ithaca contains numerous fossils, but they are not so well preserved as those 
further south in the Chemung group. Among such as were thought to be characteristic is 
the Interstriate strophomena, No. 1 of wood-cut 45, the same in all respects with the Leptaena 
interstrialis of Mr. Phillips. This fossil, according to Conrad and Hall, is also found at the 
Chemung narrows, etc. It is abundant about half way up the inclined plane at Ithaca, and is 
found at Scott’s corners near the head of Skaneateles lake, and in the quarries north of Homer. 
At these latter places, it is but little remote vertically from the Genesee slate. It therefore 
descends low, and has a wide range. 
No. 2. Ithaca strophomena (S. ithacensis), is also from the inclined plane, but it is not 
abundant, and not much is known about it. 
The fossils which will show this mass to be a distinct one, should 
it be such, will be found towards the lower part of the inclined plane ; 
for, without question, those higher up are found in the Chemung 
group. Among these latter we find the Atrypa squamosa, an Atrypa 
resembling the prisca, and the two valves which Mr. Conrad sup¬ 
poses to be the Strophomena membranacea of Phillips; the three 
considered to be Devonian fossils. The last is figured in wood- 
cut 48, at the head of the succeeding group. In the lower part of 
the mass at Ithaca are three or four species of cypricardites, an 
involute shell which appears to resemble the genus Clymenia of 
Phillips, three or four atrypae, etc. 
At the inclined plane, and at the rock of the tunnel, a very sin¬ 
gular branching fossil was found, which at first glance might be 
supposed to be a Fern, but may prove to be an intermediate to the 
crinoids and corallines; Mr. Hall having discovered in his district 
some forms of crinoids, which are somewhat analogous to it. This 
fossil is exhibited in wood-cut 46. It consists of a stem, from 
which, on both sides, short and parallel rigid branches diverge with 
extreme regularity, far more so than belongs to any known plant, or 
crinoid, where the branches were movable ; these being like the co¬ 
rallines in fixedness and regularity, probably it is intermediate to the 
two. The wood-cut was finished before it was known that Mr. 
Hall had obtained perfect specimens of the same from the tunnel. 
A fragment of a like fossil was also found on the west side of the 
lake, immediately under the Tully limestone. 
Besides these fossils, there are others at Ithaca which resemble 
those which grow upon the surface of the earth, but they present 
very little character ; showing no surface markings, varying greatly 
in size, their form being indeterminate, and the rock breaking too 
irregularly to admit of obtaining more than fragments of them. Some 
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