48 PROCEEDINGS OF UXITED STATES NATIONAL MUSEUM. 



Straight or nearly so ; lower border slightly convex and longer than the 

 upper border; posterior border nearly straight or slightly convex, trun- 

 cating the shell obliquely downward and backward, meeting the upper 

 b;)rder at a more or less distinct obtuse angle and the lower border by 

 an abrupt curve. Surfiice marked by abundant coarse lines and imbri- 

 cations of growth, which traverse the shell in slightly curved lines corre- 

 sponding with the posterior border, and is apparently without trace of 

 any radiating lines or ribs. 



Entire length from beak to postero-basal extremity about 215 milli- 

 meters ; breadth, from the postero-dorsal extremity to the base, meas- 

 ured at right angles Avith the upj^er border, 95 millimeters. 



This ehell is so unlike aay described American species that no detailed 

 comparison with any of them is necessary ; but it is so closely related 

 to F. legeriensis d'Orbigny, from the dejiartment of Sarthe, France, that 

 it is not without some hesitation that I have decided to i)ropose a sepa- 

 r;!te specific name. 1 have never had an opportunity to examine any 

 of the few examples of P. legeriensis that have teen discovered, and 

 my comparisons are therefore only with the descrii)tion and figures of 

 d'Orbigny, in Pal. Frangaise, Vol. Ill, p. 257, pi. 334. From these it 

 appears that our shell differs from P. legeriensis in the following x)articu- 

 lars. The angle of divergence of the upper and lower margins is not so 

 great, in consequence of which the breadth of the shell is not propor- 

 tionally so great ; the curve by which the posterior border meets the 

 lower border is more abrupt, and the greatest transverse diameter of the 

 shell is near the median line instead of being much below it, as it is rep- 

 resented to be in P. legeriensis. The internal median grooves upon each 

 valve, and also the undulations of the lower border, mentioned by d'Or- 

 bigny, appear to be entirely wanting in our shell. 



Position and locality. — Cretaceous strata ; about 1 J miles southwest- 

 ward from Fort Wingate, Northern New Mexico, where it was collected 

 by Mr. James Stevenson^ in whose honor the specific name is given. 



Washington, D. C, February 15, 1880. 



NOTE OIV THE OCCURBEIVCE OF STBl€Ifct,AIVI>S]\IA SAI.TERS AND 



S. I>AVni!>S»I\5 IIV <~,iJE:OISOSA. 



By C. A. WC3ITE. 



A few months ago Lieut. A. W. Vogdes, United States Army, gave 

 me a few fragmentary fossils from a collection which he had then lately 

 made at Taylor's Ridge, in the town of Ringgold, Catoosa County, 

 Georgia. Tlie other fossils of this collection and the geology of the 

 region referred to were discussed by Lieutenant Vogdes in the Decem- 

 ber, 1879, number of the American Journal of Science and Arts, pp. 

 475-477. He there refers, and doubtless correctly, the horizon from 

 which he obtained the fossils he gave me to that of the Clinton Group 



