232 NORTH STAFFORDSHIRE COAL FOSSILS. 



Position and locality : Xot rare in the Knowles iron- 

 stone, Brown mine, and generally throughout the coal-field. 



GEXUS STREPSODUS, HUXLEY. 



Strepsodus sanroides, Huxley. (Ref., Quar. Jour. Geol. 

 Soc., vol. xxii.) A tooth of this species is figured in the 

 Transactions of the Tyneside Naturalists' Field Club as 

 Holoptychius sauroides (vol. vi., pi. vi., fig. 6), a species 

 established by Agassiz and mentioned by him in his " Tableau 

 General " but not described. Teeth of this species are not 

 rare in these coal-measures. They are generally found 

 detached. In the author's collection there are two fragments 

 of a right and left ramus of the mandible. One of these 

 fragments is two and a half inches long. Its exterior surface 

 near the alveolar border is covered with small tubercles. 

 The remaining portion is of a reticulated pattern. A large 

 tooth, one and a quarter inch long, is placed at the symphis : 

 five smaller teeth, each seven-sixteenths of an inch in length, 

 are placed at a distance of about a quarter of an inch from 

 each other. The teeth are laterally compressed at the base, 

 but become more circular in the shaft. They are recurved 

 " and twice bent near the apex," and are covered with 

 fine longitudinal stria?, which in some cases cover the 

 whole of the surfaces. Generally the striation is confined 

 to the convexity of the shaft and the lateral surfaces. We 

 have specimens perfectly smooth. It remains to be seen 

 whether this peculiarity is of specific importance. 



Position and locality : Not rare in the Rag mine and 

 Deep mine ironstones, Fenton and Longton ; Knowles iron- 

 stone, Fenton ; Brown mine, Silvcrdale ; Gubbin ironstone, 

 Shelton. 



