284 



PAL.SWNTOLOGY OF NEW-YORK. 



129. 1. TENTACULITES FLEXUOSA. 



Pl. LXXVIII. Figs. 3 a, b. 



Reference pag. 92, pl. 39, fig. C of this report. 



Tentaculites. Emmons, Geol. Report, 1842, pag. 404, fig. 6. 



Compare Cormilites serpulariiis, Schlotheim. Murchison, Sil. System, pag. 627, pl. 26, figs. 5 - S. 



This species is equally as abundant in the rocks of the Hudson-river group as in the 

 Trenton limestone. In the latter it often attains a greater length, and is nearly straight or 

 simply curved. The flexuous character, therefore, may not be constant or essential in 

 distinguishing the species, though I have not seen perfectly straight specimens. In the 

 shales and ferruginous shaly sandstones of the Hudson-river group, the moulds only of this 

 species are found, and the fine longitudinal striae are rarely well preserved. It is distinct 

 from either of the species described by Mr. Muhchison, from the Caradoc sandstone.* 



Fig. 2 a. Fragment of the stone with several specimens a, a, a, associated with corals, shells, etc. 

 Fig. 2 J. A specimen enlarged, showing the longitudinal striae. 



Position and locality. In the middle and higher parts of the Hudson-river group at 

 Turin, Boonville, Loraine, Pulaski, and other places in New-York ; at Cincinnati ( Ohio ), 

 Maysville ( Kentucky ) , and Madison ( Indiana ) . 



NOTE TO THE CRINOIDEA. 



Since this volume will be published without the elementary portion, which is in pre- 

 paration, and will form a part of the next volume, the following explanations are given of 

 the signs used in designating the structural arrangement of these animals. Those only 

 are given which are used in the plates of this volume. 



B. Base of attachment. 



E. Pelvis. 



F. Costal plate or joint. 



G. Intercostal plate or joint. 

 H. Scapular plate. 



I. Interscapular plate. 



J. Irregular interscapular plate. 



K. Arms. 



L. Cuneiform joint. 



M. The hand. 

 N. The fingers. 

 Ql. Pectoral plates. 

 R. Capital plates. 



Cuneiform arm-joint. 



First. 



Second. 



Jnint, as L, first costal ; L, second costal, etc- 

 -, arm-joints. 



• In the description of this species, I had overlooked the analogy in its mode of growth to that of the Cornulitcs 

 serpulariiis, so fully illustrated by Mr. Murchison. The structure, however, is quite different, being annulated by 

 sharp equal ridges, and not composed of sections of different sizes, one proceeding from the other. The apparently 

 septate character, shown in a single large individual in the Trenton limestone, may indicate a structure incompatible 

 with the true Tentaculites. Its geological position is below that of the Cornulites serpulariiis ; and should further 

 examination and comparison prove it to be generically allied to that one, it will form a distinct species. 



