412 BULLETIN 92^ UNITED STATES NATIONAL MUSEUM. 



Dicellograptus sextans — Continued. 



Dicellograptus sextans Lapworth, Belfast Nat. Field Club, Rep. and Proc, 1, pt. 

 4, 1877, pi. 7, fig. 4.— Linnarsson, Sver. Geol. Unders., ser. C, no. 31, 1879, 

 p. 18. — Lapworth, Ann. and Mag. Nat. Hist., 5th eer., 6, 1880, p. 19; Trans, 

 Roy. Soc. Canada, 5, see. 4, 1886, p. 178.— Ami, Canadian Geol. Surv. Rep., 

 2d eer., 3, pt. 2, 1889, p. 117.— Walcott, Geol. Soc. Amer. Bull., 1, 1890, 

 p. 339.— Gurley, Jour. Geol., 4, 1896, p. 297.— T. S. Hall, Roy. Soc. Victoria 

 Proc, 9, 1896, p. 184; Geol. Mag., n. s., dec. 4, 6, 1899, p. 445.— Ruedemann, 

 Bull. New York State Mus., 42, 1901, p. 539.— Clark, Geol. Mag., 4th ser., 

 9, 1902, p. 498.— Ellas and Wood, Mon. British Grapt., pt. 4, 1904, p. 153, pi. 

 21, figs, la-e.— Dale, Bull. U. S. Geol. Surv., 242, 1904, p. 33.— Ami, Geol. 

 Surv. Canada, Sum. Rep., 1905, p. 12. — Grabau and Shimer, N. A. Index 

 Fossils, 1, 1906, p. 33, fig. 53d, e. — Ruedemann, Mem. New York State Mus., 

 11, pt. 2, 1908, pp. 306-308, pi. 19, fig. 1, text figs. 229-230. 



Dicellograptus cf. sextans TuUberg, Sver. Geol. Unders., ser. C, No. 50, 1882, p. 20. 



DicranograptUB sextans Hopkinson, Geol. Mag., 7, 1870, p. 356, pi. 16, fig. 1. — 

 Lapworth, Cat. West. Scott. Foss., 1876, p. 6, pi. 3, fig. 78.— Walcott, Trans. 

 Albany Inst., 10, 1883, p. 34 (adv. sheets, 1879). — Richardson, Terranee of 

 Orange County, Vermont, 1902, p. 63. 



Dicranograptus (Dicellograptus) sextans Roemer and Freeh, Leth. Pal., 1, 1897, 

 p. 621. 



Dicranograptus formosus Hopkinson, Geol. Mag., 7, 1870, p. 356. 



Middle Ordovician: Glenmont, Mt. Moreno, etc., New York; Vermont; Arkansas 

 (Normanskill); England; Wales; Scotland; Ireland; Sweden; and Australia. 



Dicellograptus sextans exilis Elles and Wood. 



Dicellograptus sextans var. exilis, Elles and Wood, Mon. British Grapt., pt. 4, 



1904, p. 153.— Ruedemann, Mem. New York State Mus., 11, pt. 2, 1908, pp. 



309, 310, fig. 231. 

 Graptolithus sextans (pars.) Hall, Pal. New York, 1, 1847, pi. 74, fig. 3a. 

 Middle Ordovician: Great Britain (Glenkiln); Glenmont and Mt. Moreno, New 



York (Normanskill). 



Dicellograptus sextans perexilis Ruedemann. 



Dicellograptus sextans var. perexilis Ruedemann, Mem. New York State Mus., 11, 



pt. 2, 1908, p. 310, pi. 19, fig. 2, text fig. 233. 

 Chazyan (Normanskill): Mt. Moreno, near Hudson, New York. 



Dicellograptus sextans tortus Ruedemann. 



Dicellograptus sextans var. tortus Ruedemann, Mem. New York State Mus., 11, 



pt. 2, 1908, p. 309, fig. 232. 

 Chazyan (Normanskill): Kenwood, New York. 



Dicellograptus smith! Ruedemann. 



Dicellograptus smithi Ruedemann, Mem. New York State Mus., 11, pt. 2, 1908, 



pp. 313-315, pi. 19, figs. 3-6, text figs. 237, 238. 

 Chazyan (Athens) : Near Pratt's Ferry, Bibb County, Alabama. 



Dicellograptus tenuis Lapworth. See Didymograptus subtenuis. 



DICELLOMUS Hall. Genotype: Lingula polita Hall. 



Dicellomus Hall, 23d Ann. Rep. New York State Cab. Nat. Hist., 1873, p. 246.— 

 Walcott, Mon. U. S. Geol. Sur\'., 1889, 32, pt. 2, p. 446; Proc. U. S. Nat. Mus., 

 28, 1905, pp. 312-313.— Grabau and Shimer, N. A. Index Fossils, 1907, 1, p. 

 189._Walcott, Smiths. Misc. Coll., 63, 1908, pi. 11, pp. 142, 144; Mon. U. S. 

 Geol. Surv., 51, 1912, p. 571. 



