NORTH-CAROLINA GEOLOGICAL SURVEY. 



225 



CHAPTER XVII. 



PISCES. 



Description of the remains of Fish in the> 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 ISTew 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 Korth-Carolina. 



IX)SSIL SQUALIDAE OF THE TERTIARY OF THE EASTERN COUNTIES. 



The fossil squalid ae, or sharks, are known only by their 

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

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