BIBLIOGRAPHIC LIST OF GENERA AND SPECIES. 429 



DIDYMOGRAPTUS— Continued. 



DidymograptuBHall, 20th Rep. New York State Cab. Nat. Hist., 1868, pp. 217, 2'M; 

 rev. ed. (1870), p. 251.— Zittel, Handb. Pal., 1, 1879, p. 298.— Tullberg, 

 Sverigee Geol. Undere., eer. C, No. 55, 1883, p. 12. — Hermann, Geol. Mag., 

 dec. 3, 3, 1886, p. 14.— Miller, N. A. Geol. Pal., 1889, p. 185.— Tornquist, 

 Lunds I'nivers. Arsskrift, 26, No. 4, 1890, p. 15. — Barrois, Ann. Soc. Geol. 

 du Nord, 21, Lille, 1893, p. 108.— Holm, Sveriges Geol. Unders., ser. C, No. 

 150, 1895, p. 15; Geol. Foren. Stockholm Forhandl., 17, 1895, p. 331; Geol. 

 Mag., dec. 4, 2, 1895, pp. 433, 439, pi. 14, figs. 1-3, 7, 8.— Nicholson and Mnrie, 

 Geol. Mag., dec. 4, 2, 1895, pp. 530-535, figs. — Koken, Die Leitfossilien, Leip- 

 zig, 1896, p. 328.— Wiman, Bull. Geol. Inst. LTniv. Upsala, 2, pt. 2, No. 4, 

 1896, p. 266; Nat. Sci., 9, 1896, p. 191.— Walther, Zeits. d. d. geol. Gesell., 

 49, 1897, p. 251.— Roemer and Freeh, Leth. geog., 1 Theil, Leth. Pal., 1, 

 3 Lief., 1897, p. 587.— Ruedemann, Amer. Nat., 32, 1898, p. 5; Zittel-East- 

 man Textb. Pal., 1, 1900, p. 118. — Tornquist, Lunds Univers. Arsskrift, 37, 

 No. 5, 1901, p. 10.— Ellea and Wood, Mon. British Grapt., Pal. Soc, 1901, 

 p. 5.— Ruedemann, Mem. New York State Mus., 7, 1904, p. 666, 668.— 

 Grabau and Shimer, N. A. Index Fossils, 1, 1906, p. 30. — Ruedemann, Mem. 

 New York State Mus., 11, pt. 2, 1908, p. 247; Zittel-Eastman Textb. Pal., 

 2d ed., 1913, p. 129. 



DIdymograptus acuticlens Lapworth. 



Didymograptus affinis Hopkinson, Quart. Jour. Geol. Soc, 31, 1875, pi. 33, 



figs. 6b, c 

 Didymograptus acutidens (Lapworth MS.) Ellesand Wood, Mon. British Grapt., 



pt. 1, Pal. Soc, 1901, p. 25, pi. 2, figs. 3a-d. — Ruedemann, Mem. New York 



State Mus., 7, pt. 1, 1904, pp. 683, 684, pi. 13, fig. 15, text figs. 77, 78. 

 Canadian: St. Davids District, Wales, and South Shropshire, England (Arenig); 



Deepkill, Rensselaer County, New York (Deepkill, Didymograptus bifidus 



zone). 



Didymograptus affinis Hopkinson. See Didymograptus acutidens. 



Didymograptus arcuatus (Hall). 



Graptolithus arcuatus Hall, Geol. Surv. Canada, dec. 2, 1865, p. 79, pi. 2, figs. 



e-10. 

 Graptolithus (Monoprion) arcuatus Hall, 20th Rep. New York State Cab. Nat. 



Hist., 1868, p. 226; rev. ed. (1870), p. 260; p. 223. 

 Didymograpsus arcuatus Gurley, Jour. Geol., 4, 1896, p. 96 (gen. ref.). 

 Didymograptus arcuatus EUes and W^ood, Mon. British Grapt., Pal. Soc, 1903, 



p. li (gen. ref.). 

 Canadian (Levis, Didymograptus zone): Point Levis, Quebec. 



Didymograptus bifldus (Hall). 



Graptolithus bifidus Hall, Canadian Nat. and Geol., 3, 1858, p. 164; Geol. Surv. 

 Canada, Rep. Progr. for 1857, 1858, p. 130; Geol. Surv. Canada, dec. 2, 1865, 

 p. 73, pi. 1, figs. 16-18; pi. 3, figs. 9, 10. 



Graptolithus (Monoprion) bifidus Hall, 20th Rep. New York State Cab. Nat. Hist. 

 1869, p. 226, pi. 3, figs. 13, 14; rev. ed., 1870, p. 241; p. 223. 



Didymograptus bifidus Nicholson, Quart. Jour. Geol. Soc. London, 24, 1868, p. 

 136; Ann. Mag. Nat. Hist., 4th ser., 5, p. 346, fig. 7. — Hopkinson, Quart. 

 Jour. Geol. Soc, 31, 1875, p. 646, pi. 33, figs. 8a-e.— Brogger, Diesil. Etagen 2, 

 3, etc. Kristiania, 1882, p. 41. — Herrmann, Geol. Mag.,3deer.,3, 1886, p. 15. — 

 Ami, Geol. Surv. Canada Rep., 2d ser., 3, pt. 2, 1889, p. 116k. — Barrois, Ann. 

 de la Soc. Geol. du Nord., 20, 1892, p. 92.— Files, Quart. Jour. Geol. Soc 

 London, 54, 1898, p. 511.— Elles and Wood, Mon. British Grapt., pt. 1, Pal. 



