ITHACA GROUP. 



175 



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The rock at Ithaca contains niunerous 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 

 interstriahs 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 comers near the head of Skaneateles lake, and in the quarries north of Homer. 

 At these latter places, it is but httle 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 fornid 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 ; shovring 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. Som e 



