Dr. James Geikie — Preservation of Deposits under * Till.'' 73 



section of my journey in Eastern Siberia and across Mongolia, not 

 only was everything buried in snow, but the cold was so intense 

 that I could do little more than attend to personal requirements. In 

 China, the chief detriment to the making of observations was the 

 rapidity of travel, which prevented any deviation from the track, 

 coupled with a rude and ignorant inquisitiveness displayed by the 

 inhabitants, from whom there was no escape. 



These circumstances will, I think, sufficiently explain the meagre- 

 ness of my notes, and at the same time the origin of any inaccuracies 

 should they perchance be found to have unobservedly or unwittingly 

 crept in. Here and there upon my journey, especially in Siberia, I 

 found friends who endeavoured to exchange ideas ; but unfortunately, 

 with but few exceptions, I found my ignorance of Eussian usually 

 prevented my obtaining a tithe of what I might otherwise have 

 learnt. Whilst subsequently writing out these notes, being without 

 the means of reference may in all probability have caused me to 

 jDut forth arguments either for or against which there may be much 

 evidence yet remaining to be adduced. In several instances my 

 arguments have been antagonistic to the existence of polar ice-caps, 

 but this has only been in regard to the production of certain phe- 

 nomena. All that I endeavoured to show is, if these mighty engines 

 existed, their traces must in many cases have been subsequently 

 obliterated, and what is more, many of the so-called glaciated 

 regions of the world I believe to have been produced by coast-ice 

 acting on a rising area. 



When speaking of the origin of the Siberian Steppes, as in the 

 case of the glaciated rocks I saw in Finland, I have endeavoured to 

 explain their origin by existing agencies rather than . referring to 

 those the origin and action of which were more debatable. 



What I said of the earthquakes of Eastern Siberia I gathered in 

 part from an epitome which is given of them by Messrs. Orlof and 

 Shtuikin in the Siberian Calendar for 1875. 



The remainder of my information was gathered from personal 

 observation or from persons more or less conversant with the sub- 

 jects on which I have written, to all of whom I think I have before 

 referred, and whom I now take the opportunity of kindly thanking. 



It therefore only remains for me to put my fragmentary jottings 

 forth to be sifted, arranged, and taken for their worth. In some 

 cases I may have been mistaken in my observations, or have over- 

 estimated their worth : but where this is so, feeling my fallibility, I 

 hold myself open to conviction, 



IV. — On the Pkeservation of Deposits o^ Incoheeent Materials 

 UNDER Till or Boulder- clay. 



By James Geikie, LL.D., F.R.S. 



THOSE who maintain that Till or Boulder-clay has not only 

 originated but accumulated underneath glacier-ice may some- 

 times have felt puzzled to account for the preservation of beds of 

 more or less incoherent materials below a deposit which they have 

 so many cogent reasons for believing to be a true moraine profonde. 



