NORTH-CAROLINA GEOLOGICAL SURVEY. 



225 



CHAPTEK XVII. 



PISCES. 



Description of the remains of Fish in tho North-Carolina Marl beds 



FIGS. 47 & 48. 



ISCHYRHIZA ANTIQUA. LEIDY. 



The curious genus Ischyrhiza. 

 was first brought to my notice 

 by the discovery of a tooth in 

 the Green Sand of New Jersey, by 

 Prof. Leidy. My collection con 

 tains several teeth discovered on 

 the Neuse River. In most speci 

 mens the crown has lost its apex, 

 but the fang is entire. In the per 

 fect condition, the crown has been 

 laterally compressed, conical and 

 inverted with smooth, shining en 

 amel. The fang expands from the crown in a pyramidal man 

 ner ; is quadrilateral, curved backward, and divided at base 

 antero-posteriorly ; the division becoming deeper posteriorly. 

 The larger specimen, in the figure, which is of a red color, 

 when perfect, was nearly, or perhaps quite two inches in 

 length. Its fang is an inch long, eight lines antero-perterior- 

 ly at base, and six lines transversely. The base of the crown 

 is oval in section, and measures six lines antero-perteriorly, 

 and five lines transversely. 



The smaller specimen is black in color, and was about half 

 an inch shorter than the other. Its fang is about ten lines 

 long, and at base is about six lines square. It belongs to 

 miocene of North-Carolina. 



FOSSIL 8QUALIDAE OF THE TERTIARY OF THE EASTERN COUNTIES. 



The fossil squalidae, or sharks, are known only by their 

 teeth, as these are the only parts which are usually preserved. 

 16 



