BRACHIOPODA. 
201 
1848. Orthis, Davidson-. Bull. Soc. Geol. France, 2d ser., vol. v, p. 323. 
1848. Spirifei-a, Phillips and Salter. Mem. Geol. Survey United Kingdom, vol. ii, p. 293. 
1850. Platystrophia, King. Monogr. Permian Fossils England, p. 106. 
1851. Orthis, Qoenstedt. Handb. der Petrefactenkunde, p. 486. 
1852. Spirifer, Hall. Palaeontology of' N. Y., vol. ii, pi 65. 
1852. aS pimfer, McCoy. British Palaeoz. Fossils, p. 192. 
1853. Orthis, Davidson. Introd. British Foss. Brachiopoda, plate viii, figs. 146-148. 
1856. Orthis, Billings. Canadian Naturalist and Geologist, vol. i, p. 206. 
1858. Delthyris, Rogers Geology of Pennsylvania, vol. ii, p. 820. 
1859. Orthis, Salter. Murchison’s Siluria, 2d ed., p. 210. 
1859. Orthis, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., p. 66. 
1860. Orthis, Lindstrom. Gotland’s Brachiopoder, p. 371. 
1863. Orthis, Billings. Geology of Canada, Report of Progress, p. 167. 
1865. Platystrophia, Shaler. Bull. Museum Comparative Zool., No. 4, p. 67. 
1866. Orthis, Salter. Mem. Geol. Survey United Kingdom, vol. iii, pp. 259, 267, 276. 
1871. Orthis, Davidson. British Silurian Brachiopoda, p. 268. 
1873. Orthis (Platystrophia), Meek. Geol. Survey Ohio; Palaeontology, vol. i, p. 114. 
1874. Orthis (Platystrophia), James. Cincinnati Quart. Journ. Sci., vol. i, p. 20. 
1874. Oi'this, Nicholson and Hinde. Canadian Journal, p. 158. 
1875. Orthis, White. Geogr. and Geol. Expl. west 100th Merid., p. 74. 
1875. Orthis, Miller. Cincinnati Quar. Journ. Sci., vol. ii, p. 25. 
1875. Orthis, Nicholson. Rept. Palaeontology Prov. Ontario, p. 16. 
1878. Orthis ( Platystrophia ), James. The Palaeontologist, No. 1, p. 7. 
1880. Orthis, White. Second Ann. Rept. State Bureau Stat. and Geol., Indiana, p. 487. 
1881. Orthis, White. Tenth Report State Geologist Indiana, p. 119. 
1883. Platystrophia, Hall. Thirty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 34. 
1883. [Platystrophia], Hall. Rept. N. Y’. State Geologist for 1882, pi. 34. 
1885. Oi'this, Foerste. Bull. Denison University, vol. i, p. 80. 
1887. Platystrophia, Shaler. Mem. Kentucky Geol. Surv., vol. i, pt. 3, pp. 43, 44. 
1889. Orthis, Nettelroth. Kentucky Fossil Shells, p. 35. 
1889. Platystrophia, Hall. Bull. Geol Society America, vol. 1, p. 19. 
The name Platystrophia proposed by Dr. King, has come into very general 
use for a group of orthids having a strikingly spiriferoid exterior. The hinge¬ 
line and area are long and straight and nearly equally developed on the two 
valves. Both valves are very convex, the brachial being the more so and 
bearing a very strong median fold corresponding to a deep sinus on the oppo¬ 
site valve. The valves are marked by strong, sharp plications, which 
extend over the fold and sinus, and the external surface is finely granulose, 
the latter feature being rarely well retained. This peculiar exterior, so unlike 
anything met with elsewhere in the genus Orthis, readily deceived earlier 
writers into referring the species to Delthyris or Spirifer,^ and Mr. Davidson 
* Von Bdch, lS40,.Ueber Delthyris; von Eichwald, 1840, Silur. Schichten-system in Esthland ; Emmons, 
1842,Geol. of N. Y. ; Rept. Second Dist.; Conrad, 1842, Jour. Acad. Nat. Sci. Phila.; Hall, 1843, Geol. of N. 
Y.; Rept. Fourth District; de Verneijil, Geol. de la Russie; McCoy, Synopsis Silur. Foss. Ireland; Phillips 
and Salter, Mem. Geol. Surv. United Kingdom; Hall, 1S47, 1852, Palaeontology of N. Y., vols. i and ii. 
