BIBLIOGRAPHIC LIST OF GENERA AND SPECIES. 431 



DIDYMOGRAPTUS DIVARICATES Nicholson. See Dicellograptus divaricatus. 

 DIDYMOGRAPTUS? ELEGAN8 Ruedemann. See Monograptus elegans. 



Didymograptus ellesae Ruedemann. 



Didymograptus (Leptograptus) (part.) Ruedemann, New York State Pal. Ann. 



Rep., 1902, p. 589. 

 Didymograpttis ellesi Ruedemann, Mem. New York State Mus., 7, 1904, pt. 1, 



pp. 682, 683, pi. 14, figs. 22-24, text figs. 75, 76. (Corrected to ellesse in 1908, 



Mem. 11, pt. 2, p. 134.) 

 Canadian (Deepkill, Didymograptus bifidus zone): Deepkill, Rensselaer County, 



New York. 



Didymograptus euodus Lapworth. 



Didymograptus euodus Lapworth, Quart. Jour. Geol. Soc. London, 31, 1875, p. 



645, pi. 35, fig. la-c. Elles and Wood, Mon. British Grapt., pt. 1, Pal. Soc., 



p. 21, pi. 1, figs. lOa, b. 



Ordovician (Lower Llandeilo): Abereiddy Bay, St. David's District, Wales. 

 Canadian (Upper Tetragraptus zone): Twelve miles west of Little Rock, Arkansas. 



Didymograptus extensus (Hall). 



GraptolithuK extensus Hall, Geol. Surv. Can. Rep., 1858, p. 132; Canadian Nat. 

 Geol., 3, 1858, p. 166; Geol. Surv. Canada, dec. 2, p. 80, pi. 2, figs. 11-16. 



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

 Hist., 1868, p. 195, pi. 3, fig. 12; rev. ed., 1870, p. 225, pi. 3, fig. 12, p. 228. 



Didymograptus extensus Nicholson, Ann. Mag. Nat. Hist., 4th ser., v. 1870, 5, 341, 

 pi. 7, figs. 2, 2a. Hopkinson, Quart. Jour. Geol. Soc., 31, 1875, p. 642, pi. 33, 

 figs. la-Id. Brogger, Die Sil. Etagen 2, 3, 1882, p. 40, Kristiania. Herrmann, 

 Geol. Mag., dec. 3, 3, 1886, p. 14. Lapworth, Proc. and Trans. Roy. Soc. Can., 

 4, 1887, pp. 168, 184. Ami, Geol. Sur. Can. Rep., 2d ser., 3, pt. 2, 1889, p. 

 116k. Roemer and Freeh, Leth. Pal., 1, 1897, p. 591. Elles, Quart. Jour. 

 Geol. Soc., London, 54, 1898, p. 504. Tornquist, Lunds Univ. Arsskrift, 37, 

 Af. 2, Nr. 5, 1901, p. 14, pi. 1, figs. 25-30. Elles and Wood, Mon. British 

 Grapt., pt. 1, Pal. Soc., 1901, p. 8, pi. 1, figs, la, b., text figs. 4a-d. Ruede- 

 mann, New York State Pal., Ann. Rep., 1902, p. 556; Mem. New York State 

 Mus., 7, pt. 1, 1904, pp. 668-671, pi. 13, figs. 17, 18; pi. 14, figs. 1-4; text 

 figs. 62-65. 



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



Graptolites (Didymograptus) extensus McCoy, Geol. Surv. Victoria, Prodr. Pal., 

 dec. 2, 1875, p. 29, pi. 20, figs. 1, la. 



Graptolithus constrictus Hall (part), Geol. Surv. Canada, Can. Org. Rem., dec. 2, 

 1865, p. 76, pi. 1, figs. 23-27. 



Canadian: Point Levis, Quebec (Levis, Didymograptus zone) ; Deepkill, Rensse- 

 laer County, New York (Deepkill, Tetragraptus zone); Arkansas; South 

 Scotland; Wales (Arenig); Wales (Skiddaw) ; Christiania; Scania; Australia. 

 Didymograptus extenuatus (Hall). 



Graptolithus extenuatus Hall, Geol. Surv. Canada, dec. 2, 1865, p. 75, pi. 1, 

 figs. 21, 22. 



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

 1868, p. 226; rev. ed., 1870, p. 241. 



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



Didymograptus extenuatus Elles and Wood, Mon. British Grapt., Pal. Soc., 1903, 

 p. li (gen. ref.). 



Canadian (Levis, Diplograptus dentatus zone): Point Levis, Quebec. 



