244 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



as we know, of pronounced annual rings, took place in the Autunian of France, 

 the Permian of Prince Edward Island, the Dunkard of southwestern Pennsyl- 

 vanian, the Chase of Kansas, and the Wichita of Texas." 



David White cites the fact that the plants of the Red Beds are not 

 essentially different from those of the gray shales and the limestone beds in 

 Pennsylvania and West Virginia and questions whether the red color means 

 anything in particular as to the aridity of the climate. He says: 



" It is probable that there was aridity in certain regions and during certain 

 intervals of the Permian; but there was evidently enough moisture to produce 

 most extensive glaciation, and, later, to promote the formation of coals over broad 

 areas in the great fresh-water Gondwana series laid down on the continents of 

 South America, Africa, and Asia." 



It is well to recall here a note to David White's discussion of the physiog- 

 raphy of the coal basin: 



"The rapid decrease, almost amounting to disappearance,' of the great number 

 of the very large spored lycopods during Conemaugh time (early Stephanian) 

 was no doubt due to failure of fructification caused by periods of relative drought 

 and reduction of the water-surface, such withdrawal of the water being plainly 

 indicated by the prevalent pseudoxerophytic characters observed in the swamp 

 plants of the period." 



B. CLIMATE OF THE PERMO-CARBONIFEROUS. 



The presence of the red beds across the continent, of the Roxbury tillite, 

 and the New Glasgow conglomerate are all inorganic evidence of a most 

 decided and extensive alteration in climate. Even as far west and south as 

 Oklahoma there is some suggestion of a possible decrease in temperature 

 sufficient to form ice of at least local extent. 



Taflf^ in 1909 reported the presence of a bowlder bed in the Caney shale 

 in the Wichita Mountains, Oklahoma, in which the individual bowlders bear 

 grooves and striae which he attributed to ice action and the accumulation 

 of the bowlders to floating ice. Ulrich,' in 191 1, stated his concurrence in 

 this view. "No other competent means of their transportation than ice — 

 presumably heavy shore ice — has been suggested." 



This region was visited by Woodworth later, and he also expressed his 

 concurrence with Tafif's view,'' that the bowlders and smaller stones of the 

 Caney shale have been transported by some sort of ice action: 



"Floating ice is naturally suggested as the probable agency, notwithstanding 

 that to have pan-ice at sea-level demands a greater degree of cold in this latitude 



• White, David, Origin of Coal, Bureau of Mines Bull. 38, note b, p. 56, 1913. 



'Taflf, J. A., Ice-borne Boulder Deposits in Mid-Carboniferous Marine Shales, Bull. Geol. 



Soc. Amer., vol. 20, p. 701, 1909. 

 ' Ulrich, E. O., Revision of the Paleozoic Systems, Bull. Geol. Soc. Amer., vol. 22, p. 352, 



footnote. 191 1. 



* Woodworth, J. B., Boulder Beds of the Caney Shales at Talihina, Oklahoma, Bull. Geol. 



Soc. Amer., vol. 23, p. 461, 1912. 



