CONCHOLOGICAL WRITINGS. 69 



\^ith concentric wrinkles, large valve with a depression and sinus. 

 Length 4-5, thickness 2-5 of the breadth. From the limestone of 

 Lake Erie and Ohio, silicilied blackish, about one inch. 



38. STROPHOMENES, Raf. 1820. See tract of October. L 

 Str. levigata. Yery smooth, longer valve convex, lower valve con- 

 cave, corners acute, not auriculate, contour arched and even. Length 

 4-5 of the breadth. Kentucky limestone. 2. Str. Jlexilis. Yery 

 thin, lower valve hardly concave with minute curved strias, upper 

 valve convex with minute fiexuose strias, corners acute subauriculate, 

 length and breadth equal. Limestone of Ohio, 1 or 2 inches. 



40. CURYULITES, Raf. 1819. Inequilateral, inequivalve, valves 

 elongated, curved or crooked, larger valve broader, the smaller often 

 angular. 1. G. striata, Raf 1818. Cuneate curved, base narrow, 

 end broad rounded, striated longitudinally, short alternate strias near 

 the end. In the Kentucky limestone, 2|- inches. 



41. ZONARITES, Raf. Tribe of Atremosia or imperforated 

 Terebratulites. Shell subtransversal equilateral, subinequivalve, 

 both valves convex with thick concentric wrinkles, hinge linear, beaks 

 very small. 1. Z. atrata. Nearly rounded, with large wrinkles and 

 furrows between. Length 5-6 of the breadth, thickness nearly half. 

 Perfect black shell silicified, nearly one inch, from the Knobhills, 

 disc, in 1822. 



42. Zonarytes? Tesselata, ^at Rounded, tesselated by concen- 

 tric and longitudinal wrinkles and furrows. Length 7-8 of the breadth. 

 From the Knobhills, one inch broad, has only 1 valve incrusted in 

 quartz, and with the hinge too imperfect to refer it decidedly to 

 this Genus. 



[Continuation of a Monograph of the Bivalve Shells of the River Ohio, and 

 other Rivers of the Western States. By Prof. C. S. Rafinesque. (Pub- 

 lished at Brussels, September, 1820. _) Containing 46 Species, from No. 76, 

 to No. 121. Including an Appendix on some Bivalve Shells of the Rivers 

 of Hindostan, with a Supplement on the Fossil Bivalve Shells of the 

 Western States, and the Tulositcs, a new Genus of Fossils. Philadelphia, 

 October, 1831.] 



[1] 



Hardly a dozen species of North American fluviatile bivalve shells, 

 had been mentioned by Rose. Lamark, »Say, and Lesueur, before 

 1820, when I described, in a special and ample Monograph, 15 

 species of them ! with 40 varieties, mostly discovered by myself, in 



