604 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Helopora dlyarlcata Continued. 



Elack River (Decorah): Minneapolis, etc., Minnesota. 

 Middle Ordovician (Kuckers): Esthonia, Russia. 

 Cotypes.CsA. No. 43568, U.S.N.M. 



Helopora elegans Ulrich. 



Helopora elegans Ulrich, Geol. Minnesota, 3, 1893, p. 194, fig. 11. Cumings, 32d 

 Ann. Rep. Dep. Geol. Nat. Res. Indiana, 1908, p. 837, pi. 29, fig. 9. 



Richmond (Whitewater): Blanchester, Oxford, etc., Ohio; Richmond and Ver- 

 sailles, Indiana. 



Holotype Cat. No. 43566, U.S.N.M. 



Helopora formosa Billings. 



Helopora formosa Billings, Catal. Sil. Foss. Anticosti, 1866, p. 37. 

 Helopora nodosa Billings, Catal. Sil. Foss. Anticosti, 1866, p. 38. 

 Nematopora formosa Ulrich, Geol. Surv. Illinois, 8, 1890, p. 645. 

 Gamachian (Ellis Bay) and Anticostian (Becsie River-Jupiter River): East 

 Point, East Jupiter River, East River, etc., Anticosti. 



Helopora fragilis Hall. 



Helopora fragilis Hall, Pal. New York, 2, 1852, p. 44, pi. 18, figs. 3a-f. Nicholson 

 and Hinde, Canadian Jour., n. s., 14, 1874, p. 141. Nicholson, Pal. Province 

 Ontario, 1875, p. 44, fig. 19, figs. 3, 3a. Ulrich, American Geol., 1, 18SS, 

 p. 233, fig. 2a-e. Miller, N. A. Geol. Pal., figs. 485a-e, 486 (p. 308). Ulrich, 

 Geol. Surv. Illinois, 8, p. 642, figs. 18a-e (p. 643), pi. 29, fig. 5a. Grabau, 

 Bull. New York State Mus., 45, 1901, p. 173, fig. 74; Bull. Buffalo Soc. Nat. 

 Sci., 7, 1901, p. 173, fig. 74. Grabau and Shimer, N. A. Index Fossils, 1, 

 1907, p. 152, fig. 207. 



Upper Medinan (Cataract): Western New York; Flamborough Head, etc., 

 Ontario. 



Lower Clinton: Wayne County, etc., New York. 



Plesiotype.Cat. No. 43369, U.S.N.M. 



Helopora fragilis acadiensis Hall. Not defined. 



Helopora fragilis var. acadiensis Hall, Canadian Nat. Geol., 5, 1860, p. 159. 

 Silurian: Nova Scotia. 



Helopora harrisi James. 



Helopora harrisi James, Paleontologist, No. 7, 1883, p. 58, pi. 2, figs. 2-2b. 

 Ulrich, Contr. Micro-Pal. Cambro-SiL, pt. 2, 1889, p. 45; Geol. Minnesota, 3, 

 1893, p. 195, pi. 3, figs, lib, c, 12. Whiteaves, Pal. Foss., 3, pt. 2, 1895, 

 p. 117. Simpson, 14th Ann. Rep. State Geol. New York for 1894, 1897, figs. 

 113-115 (p. 548). Bassler, Proc. U. S. Nat. Mus., 30, 1906, p. 40, pi. 7, fig. 8. 

 Cumings, 32d Ann. Rep. Dep. Geol. Nat. Res. Indiana, 1908, p. 837, pi. 29, 

 figs. 10-10b. Bassler, Zittel-Eastman Textb. Pal., 1913, p. 343, fig. 501f. 



Richmond: Waynesville. etc., Ohio; Indiana (Waynesville, Liberty); ?Stony 

 Mountain, Manitoba. 



Plesiotypes.Czt. No. 43569, U.S.N.M. 



Helopora imbricata Ulrich. 



Helopora imbricata Ulrich, Geol. Surv. Illinois, 8, 1890, p. 644, pi. 29, fig. 5. 

 Richmond: Wilmington, Illinois (Fern vale); Charleton Point, etc., Anticosti 



(Charleton). 



Observation. This form may be the tertiary segments of Arthroclema an< 

 Ulrich. 



HELOPORA IRREGULARIS Billings. See Trematopora irregularis. 



