243 



SILURIAN. 



ALG^E. 



BYTHOTREPHIS, Hall, 1847. 

 Palaeontol. New York, vol. i. p. 8. 



Bythotrephis gracilis, Hall. 



* 



Etheridge," Quart. Journ. Geol. Soc. vol. xxxiv. p. 574. 

 Geol. Survey of Canada,- Report of Progress, 1863, p. 937. 

 Hall, Palwontol. New York, vol. i. p. 62, pi. xxi. fig. 1. 

 Schimper, Traite d. Paleont. Veget. vol. i. p. 198. 



Fucoides qracilis. 



Hall, Nat. Hist. New York, Geol. part. iv. p. 69. fig. 14, 1843. 



Remarks. Goppert unites Bythotrcpliis gracilis with Chondrites antiquus, 

 Sternberg (Flora d. Sil. Devon, u. Unter Kohl. p. 434). 



Horizon. Silurian. 



Localities. Foreign. Arctic America : Gould Bay. United States : Cin- 

 cinnati, Ohio (Lower Silurian, Cincinnati Group, 

 Caradoc). Western Ontario (Lower Silurian, 

 Trenton Group). Hamilton, Ontario (Upper 

 Silurian, Clinton Group). 



Bythotrephis divaricata, Kidston, n.s. 



Remarks. This is related to Bythotrephis gracilis, Hall, but distinguished 

 from all the forms of that plant by its longer, lateral branchlets, and their 

 more numerous segments. It may eventually prove to be only a varietal 

 form of Hall's species, but after comparing the British examples with 

 authentic specimens of Bythotrephis gracilis, I think its differences demand a 

 specific distinction. 



Probably the plant figured by Jates (Trans. Geo. Soc. 2nd ser. vol. ii. 

 pi. xxvii. fig. 2) belongs to this species. His specimen came from the " Slate 

 clay at Colmore's Farm, Bromsgrove, Lickey." 



Horizon. Upper Silurian, Wenlock Shale. 



Locality. British. Shropshire : Malvern. 



Bythotrephis flexuosa, Emmons, sp. 



Bythotrephis (?}flexuosa. 



Goppert, Flora d. Sil. Devon, u. Unter Kohl. p. 452, pi. xxxv. fig. 6. 

 Hall, PalseontokNew York, Geol. vol. i. p. 263, pis. Ixix. and Ixixa. 

 Schimper, Traite d. Paleont. Veget. vol. i. p. 199. 



Fucoides flexuosa. 



Emmons, Taconic System p. 67, pi. v. fig. 3. 



Agriculture of New York, vol. i. pi. xvii. fig. 3, 1846. 



B 2 



