GEOLOGY OF STEEPROCK LAKE. 17 



represented a group of organisms related to the sponges, or possibly 

 to forms possessing characters of both the sponges and ArcHwo- 

 cyathince. 



The central cavity, radiating tubes, and general form of Atiko- 

 Jcania lawsoni (PI. 1, figs. 1-5), recall at once the lower Cambrian 

 genus Syringocnema of Taylor.' In each there is a cylindrical inner 

 cavity, an outer and inner wall with radiating tubes connecting 

 them; the tube walls are perforate in Syringocnema, and they 

 appear to be so in Atikokariia. The- presence of irregular septa in 

 Atihokania serves to distinguish the genus from Syringocnema, and 

 to cause a comparison to be made with irregularly septate genera of 

 the ArclicBocyaUiinw, such as Pycnoidocyathus Taylor (PI. XII, 

 fig. 68), and Sprirocyathus irregularis Taylor (PI. XVI, figs. 93 and 

 94).' 



A second and possibly a third species of AtUcokania is associated 

 with A. lawsoni. 



If the interpretation of the stratigraphic position of these inter- 

 esting fossils is correct they are probably older than the Pre- 

 Cambrian Beltina fauna of Montana' and quite unlike it; with the 

 possible exception of a fragment (PI. II, fig. 3) that suggests 

 Crytozoan f occidentale.' The genus AtilcoTcania has more of a 

 Cambrian aspect than we should expect to find in a very ancient 

 Pre-Cambrian fauna. The Archwocyathince are of late lower Cam- 

 brian age, and if the stratigraphic position were not well determined 

 I should be inclined to consider Atikohania as a lower Cambrian 

 genus. 



DESCRIPTION OF FOSSILS. 



Genus ATiKOK.iNiA, new genus. 



General form cylindrical, pear-shaped or somewhat irregularly 

 elongated, semi-globose. Central cavity more or less cylindrical and 

 of varied form and proportions. 



^Valls. — The outer and inner walls are more or less well-defined, 

 and they are united by a series of small, more or less hexagonal 



iLoc. cit., p. 153, PI. 14. 



2 Loc. cit. Footnotes 1, preceding page, and 1, above. 

 'Pre-Cambrian Fossiliferous Formations, Walcott. Bull. Geol. Soc. 

 America. Vol. 10, 1899, pp. 235-239. 



*Loc. cit., p. 233. PI. XXIII, figs. 1-4. 



