Yol. 50.] MR. CHAS. DAVISON ON SNOWDRIFT DEPOSITS. 485 



In the particulars mentioned above, the two theories agree very 

 closely. The first five points and the eighth are explained equally 

 well by both ; but in the remainder the balance, I think, inclines 

 slightly in favour of the snowdrift theory. 



I will now mention a few points in which the snowdrift theory 

 seems to me to have a decided advantage, in explaining objections 

 which it is more or less difficult to meet on the aeolian theory. 

 (1) It accounts more satisfactorily for the fixing of the dust-material : 

 first in snowdrifts hardened or packed by the action of sun and 

 wind, and afterwards in the frozen ground. (2) It agrees with 

 the geographical distribution of the loess, its occurrence as a fringe — 

 a partly overlapping fringe — to the glacial deposits. (3) It postulates 

 no change of climate or geographical conditions other than those 

 which nearly all are agreed did obtain during the Glacial period ; 

 and it does not require the existence of a central desiccated area. 



Lastly, the snowdrift theory gives an explanation of other related 

 phenomena, namely, the destruction of the mammoth and the pre- 

 servation of its remains, and the origin of the underground-ice 

 formation. In this it fulfils one of the most stringent tests of a 

 satisfactory theory. 



VII. The Preservation of Mammoth-remains. 



Several writers have advanced the view that the mammoth met 

 with its fate during violent storms accompanied by intense cold 

 and blinding snowdrifts. 1 In order to escape the violence of the 

 storm, animals would rush to the nearest woods (if they existed) or 

 to any sheltered place, the very spots where snowdrifts, owing to 

 the cessation of the wind, would be most thickly collected. In these 

 drifts they would frequently be snowed up, or entrapped in their 

 efforts to escape when the storm was over. As the snow gradually 

 disappeared, the deposit from it would envelop the mammoths, and 

 thus their remains, if the climate continued cold, would be embedded 

 in frozen earth, containing perhaps layers of granular snow as hard 

 and firm as glacier-ice. 



The abundance of remains in particular spots may be due partly 

 to the mammoths continually seeking the same places of shelter, 

 but chiefly, I think, to the earth being the comparatively thin 

 residual deposit from the masses of snow in which they were 

 entombed. 



VIII. Origin of the Underground-Ice Formation. 



The underground-ice formation, consisting of alternate layers of 

 ice and clay, has been described by Dall and other writers. Allu- 

 sions to layers of ice in the ground are also met with in the 

 narratives of several travellers. 2 



1 Strong wind with snowdrift produces a feeling of suffocation, which is not 

 experienced in wind without snowdrift ; see Koldewey, p. 899. 



2 W. H. Dall, pp. 104-111 ; W. H. Dall & G. D. Harris, pp. 260-68, with 

 references to other observations ; in addition to which see Lieut. Kendal, p. 64 ; 



