Fossils of the Chazy Limestone. 457 



Dedicated to Dr. J. A. Crevier of St. Hyacinth, whose zeal in 

 the science of geology promises to be productive of important 

 results. 



Locality and Formation — St. Dominique, Chazy Limestone. 



Collectors. — Sir W. E. Logan, Dr. Crevier. 



Pleurotomaria pauper, N. s. 



Description. — Shell small; whorls three or four, flat above, 

 ventricose below, and obtusely angulated at the edge of the um- 

 bilicus ; width, from four to eight lines ; height, half of the 

 length. 



The spire is perfectly flat, and the outer margin in the cast 

 acutely rounded. Below the margin the base tapers, with a gentle 

 convexity, to the edge of the umbilicus. In a specimen five lines 

 wide, the last whorl has a width of two lines on the upper sur- 

 face at the aperture, the depth from the upper side to the lower 

 angle of the aperture being also two lines, and the umbilicus one 

 and a half lines wide. In the cast of the interior, the suture is 

 deep, rounded at the edges, and the upper side of the whorls 

 gently convex. Surface unknown. 



About the size and shape of P. Crevieri, but with a perfectly 

 flat spire and an umbilicus. 



Locality and Formation. — Grenville. Chazy. 



Collector — Sir W. E. Losnw. 



Besides the above there are six other species of Pleurotomaria 

 in the Chazy, but they must remain until better specimens can 

 be procured. 



MURCHISONIA INFREQUENS, N. S. 



Description. — Elongate, slender apical, angle about 20° ; whorls 

 five or six, depressed, ventricose smooth, — the last one large, and, 

 when measured from the lower angle of the aperture, equal to 

 half the whole length. Length of the only specimen collected, 

 fourteen lines; diameter of last whorl, four lines. The surface, 

 judging from the appearance of a small fragment of the shell, 

 must be smooth, or very finely striated. 



In this species the whorls are not so convex as they are in 

 M. gracilis, and the last one is proportionally larger. 



Locality and Formation. — Grand Isle, near Cornwall. Chazy 

 Limestone. 



Collector — J. Richardson. 



