308 SYNOPSIS OF AMERICAN FOSSIL BRACHIOPODA. [hulls?. 



Pholidops trentonensis minor Winchell and Scliuclieit. Trenton (Ord.). 

 Pholiilo])8 treutouensis var. minor Winohell and Scliuchert, Minnesota Geol. Sur- 

 vey, III, 1893. p. 376, pi. 29, lig. 40. 

 Loc. St. Paul and Cannon Falls, Minnesota. 



PHOLIDOSTROPHIA Hall and Clarke, (renotype Stropliodonta nacrea 



IIall=Cbonetes(?) iowensis Owen. 

 Pholidostio])liia Hall and Clarke, Pal. New York, VIII, Pt. I, 1892, p. 287;— 

 Elevcntli Ann. Ke]). N. Y. State Geologist, 1894, p. 281. 



Pholidostrophia iowaensis (Owen). Corniferous and Hamilton (Dev.). 



Chonetes (f) io\vensi.s Owen. Geol. Survey Wisconsin, Iowa, Minnesota, 1852, p. 

 .'>84, pi. 3A, tig'. 7. [See specimens in U. S. Nat. Mus., Cat. Invert. Foss., 



17942.] 

 Chonetes sp. undet. Owen, Ibidem, 1852, \A. 3A, lig. 17. [See specimens in U. S. 



Nat. Mus., Cat. Invert. Foss., 17916.] 

 Strophomena (Stropliodonta) nacrea Hall, Tenth Rep. N. Y. State Cab. Nat. Hist., 



1857, p. 144. 

 Strophomena lepida Hall, Geol. Iowa, I, 1858, p. 493, pi. 3, lig. 3. — Billings, 



Canadian Jour. Sci. Arts, YI, 1861, p. 344. 

 Strophodonta nacrea Hall, Pal. New York, IV, 1867, p. 104, pi. 18, fig. 1; — Second 



Ann. Rep. N. Y. State Geol., 1883, pi. 46, tigs. 20-24.— Nettelroth, Kentucky 



Fossil Shells, Mem. Kentucky Geol. Survey, 1889, p. 146. 

 Stropheodonta (Pholidostrophia) nacrea Hall and Clarke, Pal. New York, A'lII, 



Pt. I, 1892, p. 287, pi. 15, ligs. 20-24; Pt. II, 1895, pi. 84, tig. 11. 

 Loc. Iowa City, Iowa; western New York; Columbus, Ohio; Falls of Ohio; Rock 



Island, Illinois; Alpena, Michigan; Ontario, Canada. 

 Obs. Owen's type specimens preserved in the United States National Museum 



prove to be identical with Strophomena lepida, which Hall in 1867 said is a 



synonym for Strojiheodonta nacrea. 



Plsesiomj^s Hall and Clarke=Dinorthis. 



PLATYSTROPHIA King. Genotype Terebratulites biforata Schlotlieim. 



Platystrophia King, Mon. Permian Fossils of England, Pal. Soc, 1850, p. 116. — 

 Hall, Geol. Soc. America, 1, 1889, pp. 19, 20.— Hall and Clarke, Pal. New York, 

 VIII, Pt. I, 1892, p. 200.— ^Vinchell and Schuchert, Minnesota Geol. Survey, 

 III, 1893, p. 4.54. — Hall and Clarke, Eleventh Ann. Rep. N. Y. State Geologist, 

 1894, p. 268. 



Obs. It is doubtful whether all the various forms of natystrophia can be regarded 

 as species. This genus is nearly always abundantly represented by one or 

 more forms throughout the American Ordovician and Silurian systems. 

 When individuals of the same region or of widely separated localities are 

 compared with each other it is apparent that the specilic characters are 

 very inconstant. Individuals of a stratum, however, are fairly constant in 

 form, size, and plications, and it is this limited constancy that has served in 

 many of the following species. 



Platystrophia acuminata James. Lorraine (Ord.). 



Orthis (Platystrophia) acuminata James, The Paleontologist, 1, 1878, \). 7. 

 Loc. Cincinnati, Ohio. 



Platystrophia acutilirata (Conrad). Lorraine (Ord.). 



Delthyris acutilirata Conrad, Jour. Acad. Nat. Sci. Philadeljihia, ^'II1, 1842, p. 



260, pi. 14, fig. 15. 

 Orthis (Platystrophia) acutilirata Meek, Pal. Ohio, I, 1873, p. 119, pi. 10, tig. 5. 

 Orthis acutilirata Miller, Cincinnati Quart. Jour. Sci., II, 1875, p. 28, 



