Dr. CroU's Theory of Glacial and Warm Periods. 105 



Dr. Croll quotes these as evidence of ice transport, but says 

 Mr. Ball, " the specimens exhibit none of the indications of 

 glacial conditions, whether we regard the character of the 

 boulders or the nature of the rock in which they are 

 imbedded." (Geo/. Mao-., "Decade III.," Vol. V., p. 232.) 

 Again returning to Mr. Prestwich — 



"There are similar palaeontological objections to ice action 

 in the Devonian and Silurian periods. Although there may 

 be at times instances in which the blocks show striae, and are 

 derived from rocks not known in the locality, it must be borne 

 in mind that such striated masses may be fragments of slicken 

 side surfaces in the rocks from which the breccias are 

 derived ; and that, although a particular rock may no longer 

 show in the locality, it may exist there buried beneath 

 newer deposits, as, amongst others, in the case of the 

 granite of the Ardennes, which, although formerly unknown 

 there, was met with in a railway cutting beneath a slight 

 covering of Palaeozoic rocks. 



" Admitting the imperfection of the geological record, it 

 is evident that, as a whole, the physical instances fail 

 entirely to supply any sufficient corroborative evidence, 

 either in force or in number, to support the theory of 

 recurrent glacial periods. Surely out of 165 or even 100 

 cases, more definite marks would have been left, especially 

 in the more recent periods, such as the pliocene and miocene, 

 when the land had assumed many of its present contours." 

 (Quarterly Journal, Geol. Society for August, 1887.) 



I will now quote another first rate observer, who is 

 speaking of the polar area, where, if anywhere, traces of 

 intercalated glacial periods ought to be forthcoming : — ■ 



In an elaborate paper published in the Geological 

 Magazine, entitled " Former Climates of the Polar Regions," 

 Nordenskiold says, inter alia : " From what has been already 

 stated, it appears that the animal and vegetable relics found 

 in the polar regions imbedded in strata deposited in widely 



