338 



G. K. GILBERT AND F. P. GULLIVER — TEPEE BUTTES. 



Heteroceras {Exiteloceras) cheyennense, M. and H. (?) 

 Heteroceras {Didymoceras) nebrascense, M. and H. 

 Heteroceras {Didymoceras) cochleatum, M. and H.(?) 

 Heteroceras, sp. undet. 

 Helicoceras, sp. undet. 



Allied Phenomena in Canada. 



Id 1886 Dr Robert Bell,"^ Assistant Director of the Geological Survey of 

 Canada, found on the Attawapishkat river, inclosed in thinly bedded 



limestones of Devonian age, a large 

 number of " great, spongy and cav- 

 ernous " limestone masses, " often 

 occupying the full height of the 

 cliffs," which is about 40 feet. 



FiGvnE i.-cuff on the Attawapishkat Biver. Thcsc " masscs are largely made 



Showing limestone cores of Devonian age. (After up of foSSils, although the number 



"^^^^•^ of species does not appear to be 



great, while the thinly bedded interspaces contain but few^" The fossil 

 forms are Meristella, Strophodonta, a trilobite and corals. The numerous 

 islets in theriver "appear to consist of single masses." 

 From the sketches by which his description is illus- 

 trated we select for reproduction views of a cliff and 

 an islet. 



These masses have so many features in common 

 with the tepee cores that their close relationship 

 can hardly be questioned. It is of interest to note, 

 also, that similarity of the topographic features to 

 which they give rise has led observers of the most 

 diverse races to employ the same analogy in the bestowal of names, 

 a recent letter Dr Bell says : 



' ' I was told that the Indians called the islets (formed of these spongy Hmestone 

 masses) wigwams, and the caverns doors, so that your name tepee agrees with the 

 name given by our Indians long ago." 



Figure 5.— Islet consisting of 

 denuded Limestone Core. 



(After Bell.) 



In 



Theories for the Origin of the Cores. 



concretion theory. 



Calcareous concretions are of so frequent occurrence in argillaceous 

 deposits that concretionary action was the first explanation to suggest 

 itself when attention was directed by the senior author to these lime- 

 stone masses imbedded in shale. It served for some time as a working 

 hypothesis, but gradually became less satisfactory as data were accumu- 



*Greo]. and Nat. Hist, Survey of Canada, Ann. Rept., vol. 2, 1886, pp. 27 G, 28 G, and 1 plate. 



