430 BULLETIN 92^ UNITED STATES NATIONAL MUSEUM. 



Dldymograptus bifldus — Continued. 



Soc, 1901, p. 42, figs. 26a-b, pi. 4, figs, la^f; p. 6, figs. 1, 2.— Ruedemann, 

 New York State Pal. Ann. Rep., 1902, pp. 566, 567; Mem. New York State 

 Mus., 7, pt. 1, 1904, pp. 689-692, pi. 15, figs. 1-3, text figs. 86, 87.— Grabau 

 and Shimer, N. A. Index Fossils, 1, 1906, p. 31, fig. 47c, 48. 

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

 Rensselaer County, New York (Deepkill, D. bifidus zone); Nevada; South 

 Scotland and Wales (Arenig) ; England; Scandinavia; Bohemia; France. 



Didymograptus bipunctatus (Gurley). 



Didymograpsus bipunctatus Gurley, Jour. Geol.,4, 1896, p. 65, pi. 5, figs. 7, 7a. 

 Canadian (Levis): Near Point Levis, Quebec. 



Didymograptus caduceus of authors. See Tetragraptus similis, Didymograptus 

 (Isograptus) caduceus and T. similis. 



Didymograptus (Isograptus) caduceus (Salter). 



Didymograpsus caduceus Salter (part). Quart. Jour. Geol. Soc. London, 9, 1853, 

 p. 87, fig. la; ibid., 19, 1863, p. 138, fig. 13a. 



Graptolithus caduceus Chapman, Canadian Jour., n. s., 1, 1856, p. 390, fig. 3. 



Graptolites (Didymograpsus) caduceus McCoy, Pal. Geol. Surv. Victoria, Prodr. 

 Pal. Victoria, dec. 2, 1874, p. 30, pi. 20, figs. 3-5a. 



Didymograptus caduceus T. S. Hall, Proc. Royal Soc. Victoria, n. s., 8, 1896, p. 69. 



Didymograptus (Isograptus) caduceus Ruedemann, Mem. New York State Mus., 

 7, pt. 1, 1904, pp. 693-698, pi. 15, figs. 6, 7, text fig. 89. 



Tetragraptus caduceus Brogger, Die Sil. Etagen 2, 3, Kristiania, 1882, p. 39. 



Didymograptus gibberulus Nicholson, Ann. Mag. Nat. Hist., 4th ser., 16, 1875, 

 p. 271, pi. 7, figs. 3, 3a, 3b.— Moberg, Geol. Foren. Stockh. Forh., 13, 1891, 

 p. 221.— Holm, Sver. Geol. Und. Afh. och upps., ser. C, No. 150, 1895, p. 18.— 

 Elles, Quart. Jour. Geol. Soc, 54, 1898, p. 496.— Files and Wood, Mon. British 

 Grapt., pt. 1, Pal. Soc, 1901, p. 52, figs. 33a, b; pi. 2, figs. 9a-e. 



Didymograptus (Isograptus) gibberulus Roemer and Freeh, Leth. Pal., 1, 1897, 

 p. 93, fig. 161. 



Isogi-aptus gibbenilus Moberg, Geol. Foren. Stockh. Forh., 14, 1892, p. 346, pi. 8, 

 figs. 3-7.— Tornquist, Lunds Univ. Arsskrift, 37, Afd. 2, 1901, p. 23, pi. 3, 

 figs. 16-19. 



Tetragraptus bryonoides Etheridge, jr., Ann. Mag. Nat. Hist., 4th ser., 1874, 14, 

 p. 2, pi. 3, figs. 3, 4. 



Phyllograptus stella Hopkinson, Quart. Jour. Geol. Soc. London, 31, 1875, p. 

 658, pi. 34, fig. t). 



Lower Ordovician: England (Skiddaw); Wales (Arenig); Scandinavia; Aus- 

 tralia; Deepkill, Rensselaer County, New York (Deepkill, Didymograptus 

 bifidus zone); Point Levis, Quebec (Levis, Diplograptus dentatue zone); 

 Arkansas. 



Didymograptus caduceus nanus Ruedemann. 



Didymograptus caduceus nanus Ruedemann, Mem. New York State Mus., 7, pt. 



1, 1904, p. 698, pi. 15, figs. 8, 9, text fig. 90. 

 Canadian: Deepkill, Rensselaer County, New York (Deepkill, Diplograptus den- 



tatus zone); Point Levis, Quebec (Levis, D. dentatus zone); Arkansas. 



Didymograptus cuspidatus Ruedemann. 



Didymograptus cuspidatus Ruedemann, Mem. New York State Mus., 7, pt. 1, 



1904, pp. 684, 685, pi. 13, fig. 16, text figs. 79, 80. 

 Canadian (Deepkill, Diplograptus dentatus zone): Mt. Moreno, Columbia County, 

 New York. 



