364 A. W. GRABAU — SILURO— DEVONIC CONTACT IN NEW YORK 



of the Buffalo cement quarry. A detailed description with illustrations 

 of transverse sections is given by Penhallow. 



CYATHOPH YLLVM HYDRA ULICUM SIMPSON 

 i Plate 21, figures la-d.) 



1900. Cyatkophyllum hydraulicum Simpson (MSS.). Memoir of the New York State 

 Museum. "The Genera of Paheozoic Corals." (In presn.) 



Corallum simple, conico-cylindrical, usually long and slender. Growth 

 irregular, with numerous abrupt changes in direction. Surface of the 

 mature portion longitudinally ribbed by numerous rounded costal 

 ridges, which are strongly marked and separated from each other by 

 a sharply depressed line. Epitheca well developed, the numerous lines 

 of growth strongly marked on the surfaces of the costal. The epitheca 

 is thrown into frequent coarse wrinkles which give the coral a ver} T 

 rugose appearance. 



The young corallum is usually destitute of costse, and is subcylin- 

 drical in form, barely increasing in diameter through a length of over 

 half an inch. It is strongly marked by the wrinkles and lines of growth 

 of the epitheca, which are sometimes quite sharp. At the end of this 

 youthful stage the corallum rapidly expands, often abrupt! y so, and the 

 costse quickly become prominent. 



Calyx of moderate depth, the total depth being usually somewhat less 

 than the greatest diameter of the calyx. Septa numerous, strong but 

 thin, and separated by interspaces from two to three times their width. 

 They retain a uniform width from periphery to center. Bottom of 

 calyx often flattened in the center; the septa meet and become slightly 

 twisted. They not infrequently unite before they reach the center. 

 Dissepimental structures appear to be well developed. No fossula 

 occurs. 



The corallum is not infrequentl v curved, the primary septum then 

 appearing on the convex side. The remarkable cylindrical, non-costate 

 young with strongly wrinkled epitheca, and the usually abrupt appear- 

 ance of the costre, and the concomitant rapid expansion of the corallum 

 are the most striking features of this coral. No internal structure has 

 been observed, as the fossils are nearly all represented by hollow molds. 

 From these, gutta-percha casts can readily be made which will show- 

 all the external characters of the corallum in great clearness. No well 

 preserved coral has been found so far, the only cases where the coral 

 was preserved at all being rendered worthless by the crystallization of 

 the whole interior, thus destroying all structural features. 



These corals are abundant in the upper three or four feet of Manlius 



