Winclicll.] ^'-'^ [Jan. 4, 



little below the level of the straight indented hinge line. The greatest 

 thickness of the shell is therefore near the flattened dorsal border. From 

 this ridge the lateral surfaces proceed with slight curvature to the ventral 

 margin, so that the united valves present a cuneate or somewhat axe-like 

 form. 



Length, one inch ; height, thirteen-sixteenths ; transverse diameter, 

 nine-sixteenths. 



This species is less elongate than Gypricardia rigidn, and has a round- 

 ed, instead of truncate posterior extremity ; the umbonal ridge, also, is 

 nearer the hinge margin. 



Collected by Rev. H. Herzer, at Newark, Ohio. 



Sanguinolites Marshalleksis, Win. 



Occurs in bed No. 4, Sciotoville, Ohio. 



Allobisma (Sedgwickia) Hankibaleksis, Shum. (Mo. Rep. p. 20G). 

 Specimens from Newark, Ohio, agree better Avith the Burlington (Iowa) 

 forms usually referred to this species, than with Dr. yiiumard's figure of 

 the type* 



Ctpeicardia (?) EiGiDA, W. & W. (Bos. Proc. yilT, 300.) 



A single specimen from Newark, Ohio, which does not show the "second 

 ridge" between the main umbonal angle and the hinge, and which may 

 result from, dorso-ventral compression. 



Leda bellistriata ? Stephens (Am. Jour. Sci. [2 J vol. XXV, p. 26.) 

 Five specimens from dark, bituminous Shales, Tennessee, are referred to 

 this species solely on account of external resemblances. They have the 

 jjeculiar form and sharp concentric furrows of the species. They are a 

 little over an inch in length, but do not, in this, exceed specimens from 

 Battle Creek, Michigan, — the typical locality. At the same time, no in- 

 dication of hinge-structure has been observed, and the shell seems to have 

 been thinner than usual for the species of this family. Should further 

 discovery demonstrate that these specimens do not belong to Leda, they 

 will perhaps fall into the genus Sedgioickia of McCoy ; but I do not con- 

 sider it allowable to propose a specific name to be based on discoveries of 

 some future investigator. 



CoNOCAEDitJM PXJLCHELLtiM, White & Whit. (Proc. Bos. Soc. N. II. 

 VIII, 299.) From Newark, Ohio. 



SoLEN scAiiPEiFORMis, Win. (Proc. Acad. N. S., Phil. Sep., 18G2, p. 

 42P.) From dark, bituminous shales, Tennessee. Like other species in 

 the same situation, the sliell is thin and fragile. This probably resulted 

 from an insufficiency of calcareous matter in the waters which precipi- 

 tated the argillo-bituminous materials of the rock. 



SoLEN QTJADRAKGTJLAEis, Win. (Proc. A. N. S., Phil. Jan., 1862.) A 

 fragment from Granville, Ohio. 



Platyceras Herzeri, n. sp. 



Shell rather large, consisting of about two coils, which enlarge rapidly 

 near the apex, and gradually through the last half of the whorl ; laterally 

 comjjressed, and dorsally sub-angulated, except near the aperture ; irre- 

 gularly plicated longitudinally, and marked transversely by deeply waved, 



