236 DESCRIPTION OF VERTEBRATE REMAINS, CHIEFLY 



The length of the specimen in its present condition is three inches five lines ; 

 its breadth three inches. Seven median teeth occupy an extent fore and aft of 

 25| lines, or 2^ lines less than in the preceding specimens. The median teeth 

 are 32 lines in breadth, and 4 lines fore and aft. 



Myliobates obesds. 



Leidy : Proceedings Academy Natural Sciences, 1855, 396. 

 Myliobates rugosus, Leidy : Ibidem, 395. 



In the neighboring State of New Jersey, in excavating the green sand marl, 

 extensively employed as a fertilizer, many vertebrate fossils are found, mainly 

 consisting of remains of reptiles and fishes. Three distinct marl beds are recog- 

 nized alternating with beds of sand, clay, and limestone, all conformable with one 

 another, and until recently all regarded as pertaining to the cretaceous period. 

 Latterly, the lower two marl beds have been considered as of the cretaceous 

 period, while the upper one has been viewed as belonging to the early tertiary 

 or eocene period. Many fossils of the different marl beds have been presented to 

 the Academy, and though having attached what is recorded as the name of the 

 locality, this is usually that of the nearest town or village, while the particular 

 bed from which they were obtained has been rarely designated. As a result we 

 are frequently perplexed in attempting to ascertain the relative age of the fossils, 

 which were once all ascribed to the cretaceous period, and which are now in part 

 considered to belong to the eocene period. 



Among the fossils of the marl beds presented to the Academy, there are many 

 remains of fishes of which the teeth of sharks greatly predominate. The collection 

 of the Academy contains a large and beautiful series of well-preserved teeth viewed 

 as belonging to Car char odon angustidens* and Otodus ohUquus. The greater number 

 of these are from the neighborhood of Vincenttown, Burlington Co., N. J., presented 

 by Col. T. M. Bryan. The two species were originally described by Agassiz, from 

 teeth found in the tertiary deposits of Europe, and we may therefore suppose that 

 the teeth from New Jersey ascribed to the same species were obtained from the 

 upper or eocene marl bed. 



Among the remains of fishes from the New Jersey marl beds there are also 

 specimens of the dental armature of Eagle-rays, and as similar remains in Europe 



* Gibbes (Journal A. N. S., 1847-50, p. 146) refers to some of thespecimens as pertaining to another species 

 with the name of C. acutidens founded on teeth from the eocene limestone of South Carolina. His views of 

 these teeth (PI xxi., figs. 39-44), and such is also the case with the New Jersey teeth, are actually more like 

 those of G. angustidens, as represented by Agassiz in the Poissons Fossiles, than those, likewise from the eocene 

 of South Carolina, which Gibbes refers to the latter named species. 



