78 [April, 



Centemodon* sulcatus. Tooth smooth, rather thick, slightly curved, with 

 trenchant edges, rounded on the exterior portion, sulcate on the lower part near 

 the base, ccrered with very minute distinct stri?e from the point to the base, 

 which strice cross the sulcations in slightly oblique lines. Length sixteen- 

 twentieths of an inch, greatest breadth four twentieths of an inch ; pulp cavity 

 large. 



On comparing this tooth with C/epsi/saurus Pe/wsi/lvanicus, which he had de- 

 scribed from the same Red Sandstone Formation in Lehigh county, it will be 

 found to differ very widely. The edge is not serrate on any part like that genus, 

 nor is it so large or so attenuate. The form, too is more compressed. It differs 

 from the teeth of Bathygnathus boreaUs, Leidy, from the New Red Sandstone of 

 Nova Scotia, in size, being smaller and being more attenuate, as well as in 

 having a trenchant smooth edge and not a serrate edge. It is about the size and 

 approaches the form of Prof. Owen's figure of Labyrinthodon, plate 63, A. f. 2, of 

 Odontographia, but it is more flattened. 



Mr. Lea als: stated that in thegreenish and blackish shales of the same locality 

 he found two species of Posidonia, which genus is so characteristic of this portion 

 of the formation and existing in immense quantities. As they seem to differ 

 from that figured by Sir Charles Lyell, in his Elementaiy Geology, as coming 

 from Oolitic coal shale of Richmond, Virginia, Mr. Lea proposed the names of 

 P. ovata and P. parva, the first being about seven-twentieths of an inch in 

 transverse diameter. The latter is more rotund, and about three-twentieths of 

 an inch in transverse diameter, both being covered with numerous minute con- 

 centric costffi over the whole disc. 



Near to this locality and superimposed, Mr. Lea obtained a specimen of impure 

 dull red limestone, which contained, on a partially decomposed surface, im- 

 pressions presenting the appearance of Foot-marks, somewhat like Chelkhnus 

 Duncani, Owen, figured by Sir Wm. Jardine in his Ichnology, for which Mr. Lea 

 proposed the provisional name of Chelkhnus Wymaniamis, after Professor Wj* man, 

 of Cambridge, Mass. 



From the same formation and locality were procured the impressions of plants, 

 some of which belong to the Conifera. One of the cones was nearly six inches 

 long and full an inch wide. These were accompanied by other plants of very 

 obscure character, covering large portions of the surface of some of the layers. 



Mr. Lea also mentioned that he had observed the same Red, Black and Gray 

 Shales at Gwinnedd, on the North Pennsylvania Railroad, where he found the 

 same Posidonicp, and some of the same obscure plants, impressions of which 

 covered the surfaces of many of the rocks. A single specimen was obtained 

 of a plant with long leaves some-whatrasemhling Xoeygerathia cuneifolia, Broguiart, 

 which is from the Permian. 



In the Black Posidonia Shales was found a single Ganoid scale, which is more 

 like Pyyopteris matidibitlaris, Agas. , from the Marl Slate (Lower Permian) than 

 any other which had come under Mr. Lea's notice. There were other obscure 

 forms observed, which have not yet been satisfactorily found to be analogous to 

 any known forms, but which Mr. Lea hoped to be able to make out when he 

 should figure all the specimens and describe them more at large for the Journal 

 of the Academy. 



Jpril 2'ld. 



Vice-President Bridges in the Chair. 



A paper was presented from J. S. Newberry, M. D., intended for pub- 

 lication in the Proceedings, entitled, " Descriptions of several new 



* KivTM/za aculeus and hic,v( dens. 



