322 



PALJEONTOLOGY OF NEW-YORK. 



in the rocks of New-York j and the other corals arc similar to those of the Niagara group, 

 wliilc none of them have ever been found in the tentaculite limestone with which it is grouped. 

 Tracing tliis rock from Herkimer county, it becomes more distinctly developed, and better 

 exposures are seen, till we have it presenting the characters noticed at Schoharie. At this 

 place a portion of the mass is a concretionary limestone, if this character be of any importance 

 in the identification of the two masses. Its position, I hold, however, is sufficient to entitle it 

 to rank as of the same age with the Niagara group ; and though many of the fossils are 

 distinct, there are still many which are identical ; and when we recollect that the conditions 

 under which the sediment in the western and the eastern part of the State were deposited 

 were very different, and that the depth of the sea was unequal, we shall find an explanation 

 for this dilfcrence in the fauna. 



In order that no confusion may arise from a mingling of the fossils from the Niagara group, 

 as known in Western New-York and in Canada, as well as still farther to the west, with the 

 fossils of the Coralline limestone around the base of the Helderberg, I have given them on 

 separate plates, and by this means a comparison between the two will be facilitated. 



The most remarkable and peculiar fossils of this rock at Sclioharic, arc the large spiral 

 univalve shells, some of which are probably true Gasteropoda, but one or two of which have 

 apparently a separate structure like the Cephalopoda. All these, together with one or two 

 species of Bellerophon, are forms unknown in the Niagara group in Western New-York. 



679. 3. DIPLOPHYLLUM CORALLIFERUM {n. sp.). 



Pl. LXXII. Fig. 1 a, b, c. 



Csespitose, growing in small tufts ; stems small ; central area small ; interior structure not 

 known. 



Two groups of this species have been observed, both of which have the spaces between the 

 stems and the entire mass surrounded and overgrown by a species of SxROMAToroRA. We may 

 infer from this fact that the conditions of the locality were not favorable to the existence of this 

 coral ; since, after attaining so small a size, it has been completely enveloped in another 

 coral of, apparently, much slower growth. 



The stems are smaller than the species previously described, and the central area propor- 

 tionally less. There are also numerous small stems among the full grown ones upon the 

 surface of the mass, where the ends are presented. This character is not observed in the Lock- 

 port species. 



Fig. 1 a. The ends of numerous stems of this coral, enclosed in a mass of Stromatopora. 

 Fig. 1 i & 1 c. Enlargements from diflcrent cells of this coral. 



Position and locality. From the Coralline limestone at Schoharie. 



(Collection of John Gebiiard junior.) 



