44 



PAL^ONTOLOat OF NEW- YORK. 



This fossil occurs in the calcareous shales of the Clinton group, usually replaced by silex ; 

 the best specimens, however, being those which are weathered from the rock. In consequence 

 of the silicified condition of the mass, the internal characters are not so clearly preserved as 

 they would otherwise be. This is the earliest known form of this type, evidently representing 

 the Syringopora which occurs in a higher position. It is associated with Catexipora in the 

 same strata, and is apparently a closely allied genus. 



Fig. 1 «. A portion of a hemispheric mass, showing the mode of growth. 



Fig. 1 i. A small fragment where the tubes are parallel. 



Fig. 1 c. Showing the tubes surrounding and radiating from some foreign cylindrical body, upon 



which the polyps have grown. 

 Fig. 1 d. Several tubes enlarged. 



Fig. 1 e. Transverse section, showing the stellate orifices of the tubes. 

 Fig. ly. A similar section, where the cells are hollow. 



Position and locality. Shales of the Clinton group, Ontario, Wayne county, and in the 

 debris about Rochester and other places. (State Collection.) 



422. 1. CATENIPORA ESCHAROIDES. 



PL. XVIII. Fig. 2. 

 For reference and synonyms, see Catenipora under Niagara group. 

 This figure is given here to show the existence of Catenipora at the period of the Clinton 

 group. It occurs in the iron ore beds and in the calcareous strata, though somewhat rarely, 

 and usually in an obscure condition. The earliest appearance of the Genus Catenipora is 

 therefore almost coincident with that of Pentamerus ; the P. ohlongus occurring in great 

 numbers only a few feet below the Catenipora.) though the latter, in its higher positions, is 

 ■widely separated from the P. oblongus in the western part of New- York. 



Gbnus HELOPORA {nov. gen.). 

 [Gr. HXo?, clavus, and •ffopog, porus.] 



Simple or branching cylindrical stems, often swelling at the upper extremity, poriferous on 

 all sides ; pores oval or subangular, arranged between longitudinal elevated lines. 



This genus is constituted to receive, more especially, a species of coral very common in the 

 calcareous layers of the Clinton group. It usually occurs in fragments, appearing like small 

 spines or tentacles : more perfect specimens are clearly celluliferous. 



423. 1. HELOPORA FRAGILIS {n. sp.). 



Pl. XVIII. Fig. 3o-/. 



Corallum minute, cylindrical or clavate ; pores oval or subangular, having a spiral direction 



