FOSSILS OF THE COAL ME ASCII KS. 609 



which appears to he wider than the dorse-ventral diameter 

 of the volution at the aperture. The surface is without 

 longitudinal lines, but the striae of growth are moderately 

 distinct, especially on the broad flattened outer side, where 

 they make a deep backward curve in crossing, so as to in- 

 dicate the presence of a very deep sinus in the lip on that 

 side of the aperture of the shell. 



In the specimen described the substance of the shell is 

 thin, and scarcely mineralized, though it retains no pearly 

 lustre. 



Position and locality Carbon Cliff, Rock Island county. 111. Roof 

 <f Coal Xo. 1. For the fine specimen from which the foregoing descrip- 

 tion was made out we are indebted to WILLIAM S. THOMAS, Esq., who 

 found it at the locality above cited. 



NAITILUS (TE.MXOCHEILUS) WUTSLOWI, M. and W. 



PL 3-i Fig. 2. 



Xautilu* ( Temnaeheiliu) Wiruiloici, MEEK and WORTHEX, 1870. Proceedings Acad. Xau Sc-i., Phila., 

 p. 50. 



SHELL attaining a moderately large size, subdiscoidal ; 

 periphery broad and nearly flat, the middle third being 

 rather distinctly flattened, while on each side of this there 

 is a very slight slope outward to the lateral margins. Um- 

 bilicus broad, moderately deep, and showing nearly the full 

 breadth of each inner volution on each side. Volutions 

 apparently about four and a half, with transverse diameter 

 nearly one-third greater than the dorso-ventral ; each orna- 

 mented around the lateral margins of the broad periphery 

 by about sixteen very prominent rounded nodes, which pro- 

 ject obliquely outward, at an angle about intermediate be- 

 tween the general plane of the shell and that of the broad 

 periphery, those on opposite sides being alternately ar- 

 raiiiivd: from these rows of nodes the sides slope abruptly 

 inwards, with a moderate convexity, to their inner mar- 

 gins within the umbilimis. Surface marked by rather well 



