136 PALEONTOLOGY OF NEW YORK. 



The striae, originating at the suture, are first directed backward, and 

 thence, gently curving over the nodes, become nearly vertical and thus 

 continue to near the peripheral carina, where they are turned a little 

 backward, and, passing this elevation, they are directed with a slight 

 curve towards the columella. 



This fossil possesses all the characteristic features of the Linnaean genus 

 Turbo, to which it was originally referred by M. de Verneuil, who described 

 and named it in honor of the late Prof. B. F. Shumard of St. Louis. It differs 

 so essentially from any other fossil of the Upper Helderberg formation, that 

 there are no other forms for comparison. In many of its features it reminds 

 one of the recent Turbo heteroclita, but it is more rotund and the columellar lip 

 is solid and more extended. In its external characters it presents some 

 interesting resemblances to Palceotrochus Kearneyi. The surface striae are in all 

 respects similar to those of that fossil, and their curvature is made in precisely 

 the same manner. The peripheral carina is almost identical in character, 

 except where it may be invaded by the nodes from above. The range of 

 nodes in the Turbo is represented by the obscure elevations in similar position 

 on the Trochus. In the general form of the shell, aperture and columella, 

 there are no points for comparison. 



This beautiful fossil, having never been redescribed in America, has been 

 nearly lost sight of, and I believe the name is scarcely or not at all known in 

 our catalogues of fossils. The shell is usually silicified, and is rarely well 

 preserved, though a few good specimens are known. It is nevertheless not 

 rare, as is shown by numerous casts of the interior occurring in some of the 

 western localities. The individuals illustrated are from the cabinet of Dr. 

 James Knapp, of Louisville, and are the best specimens known to me. An 

 imperfect specimen of large size exists in the collections of New York State 

 Museum. 



It is worthy of notice that, among all the American fossils, there has not 

 been found in the older rocks so complete representation of the genera Turbo 

 and Trochus as in these examples, both of which occur in the same formation. 



