THE 



GEOLOGICAL MAGAZINE. 



No. CIV.— FEBRTJARY, 1873. 



OI^IG-I^^^AuXJ j^i^tioijES. 



I. — On the Theory of Seasonal Migrations during the 



Pleistocene Period, 



Bt James Geikie, F.R.S.E., 



District Surveyor, Geological Survey of Scotland. 



(PLATE IV. Fig. 1.) 



IN a paper recently read before the Geological Society,^ Mr. 

 Dawkins has re-stated his views concerning the climate of 

 the Pleistocene period, and has replied to certain objections to his 

 theory brought forward by myself in former numbers of this 

 Magazine.^ After carefully reading the paper referred to, I find 

 no reason to alter or modify what I hare written upon this 

 question. Mr. Dawkins has unfortunately missed the point of my 

 objections ; and my argument, as it seems to me, remains unanswered. 

 But as that gentleman has introduced some new matter into his 

 own argument, I shall endeavour as briefly as may be to review 

 his position. 



In his former papers Mr. Dawkins contented himself with 

 stating his opinion that the appearances presented by our river- 

 gravels and cave-deposits were only explicable on the assumption 

 that something like a Siberian climate had characterized Europe 

 during Pleistocene times. He did not, however, tell us how such 

 a climate was induced or could be induced imder the physical 

 conditions which are inferred to have obtained during the last 

 continental state of the British area. He now informs us that 

 the climate he postulates was brought about by " the extension 

 of a large mass of land from the equator to the polar circle. Such 

 a mass of land extended from the range of Atlas northwards to 

 the snowy regions of Scandinavia during the Pleistocene age, the 

 Mediterranean being reduced to two land-locked seas, and the 

 mainland of Africa being continued on the one hand into Spain, 

 and on the other, by Malta and Sicily, into Italy, and Greece 

 extending so far south as to embrace Candia. Such an extent of 

 land," he continues, "is surely an exact parallel to the two cases 

 which I have quoted above (viz. North America and Northern 

 Asia) ; and climatal extremes must necessarily have been the result 

 of the substitution of land for such a large area that is now covered 

 by the sea." This is a wonderful conclusion, and one which I feel 



1 See Quart. Journ. Geol. Soc, 1872, vol. xxviii., p. 410. 



2 Geol. Mag. Vol. IX. pp. 164, 215. 



VOL. X. — NO. CIV. 4 



