NIAGARA GROUP 



257 



Fig. 5 I. A profile or cardinal view of the preceding specimen, showing the strong elevated 

 laminae for muscular attachment. 



This feature of the interior is quite peculiar, and is alone sufficient to distinguish 

 the species. 



Position and locality. This species is more abundant in the vicinity of Rochester, than at 

 any other locality examined. It is also common at Marshall's mill in Sweden, and at Wolcott 

 in Wayne county, and less abundant at Lockport and other v^'estern localities. In England, it 

 occurs in the Wenlock Limestone, and in the same position in the Island of Gothland. 



448. 23. LEPT^NA DEPRESSA. 



PL. LIII. Fig. 6a-l. 



Dritte jinomiten art mit breiter schlosskante. Hupsch, Naturg. des Neiderdeutscliland, 1781, 



Vol. 1, pa^. 15, pi. 1, fig. 7 & 8. 

 j^nomites rhomboidalis. Wahlenberg, Acta Soc. S. Upsaliensis, 1821, Vol. viii, pag. 65, no. 7. 

 Producta depressa. Sowerby, Genera of Shells. 



— — Id. Min. Conchology, 1825, Vol. v, pag. 86, pi. 459, fig. 3. 



Producta rugosa. Hisingek, Vet. Acad. Handlingar, 1826, p. 33. 

 Productus depressus. Defranc, Diet, des Sciences naturelles, 1826, Vol. xlvii, 353. 

 Leptana rugosa. Dalmaiv, Vet. Acad. Handlingar, 1827, pag. 106, pi. 1, fig. 1. 

 Leptana depressa. Id. Ibid. pag. 107, pi. 1, fig. 2. 



Strophomena rugosa. Bronn, Leth. geognostica, 1825, Vol. i, pag. 87, pi. 2, fig. 8. 

 Producta depressa. Phillips, Geol. Yorkshire, 1846, Vol. ii, pag. 215, pi. 8, fig. 18. 

 Productus depressus. Deshayes, 2d Edit. Lamarck An. sans vertebres, Vol. viii, p. 380. 

 Leptcena rugosa and L. depressa. Hisinger, Leth. suecica, 1837, pag. 69, pi. 20, fig. 2 & 3. 

 Orthis rugosa. Von Buch, Ueber Delthyris, 1837, p. 70. 

 Leptcena. Fischer, Oryct. du Gouv. du Moscou, 1837, p. 143. 



Leptana depressa. J. Sowerby in Murchison's Sil. System, 1839, pag. 623 & 636, pi. 12, fig. 2. 

 L. tenuistriata[l'\. Id. Ibid. pag. 636, pi. 22, fig. 2 a. 



L. rugosa. Id. Trans. Geol. Soc. London, 1840, 2d series, Vol. v, pi. 5%, fig. 4. 

 Orthis rugosa. Eichwald, Sil. Syst. in Esthland, p. 162. 

 Leptana rugosa. Phillips, Pal. Fossils, 1841, pag. 67, pi. 24. fig. 95. 

 L. depressa. De Koninck, Desc. An. Foss. de Belgique, 1842, pag. 215, pi. 12, fig. 3, 4, 6, 6 ; 



pi. 13, fig. 6. 

 L. — G. B. Sowerby, Conch. Manual, 1842, pag. 71, and pag. 300, fig. 206. 



Orthis rugosa. D'Archiac and De Verneuil, Trans. Geol. Soc. London, 1842, 2d series, 



Vol. vi, part 2, p. 396. 

 Strophomena depressa. Vanuxem, Geol. Rep. 3d Dist. New-York, 1842, pag. 79, fig. 5. 

 S. undulata. Id. Ibid. pag. 139, fig. 3. 



-S. depressa. Hall, Geol. Rep. 4th Dist. New-York, 1843, pag. 77, fig. 5 ; pag. 104, fig. 2. 

 Orthis rugosa. C. F. Rcemer, Rhein. Uebersgangsgebirge, 1844, pp. 85 & 90. 

 Lept<zna depressa. De Verneuil, Geol. Russia and the Urals, 1845, Vol. ii, pag. 234, pi. 15, 



fig. 7. 



Shell semioval or semicircular ; hinge-line equal to,- or extending beyond the width of the 

 shell ; dorsal valve having the upper part nearly flat, slightly convex or even concave, with 



[ PAiJEONTOLOOT — VoL. II.] 33 



