MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 659 



under three glaciers near their lower extremities, without discovering anything 

 like boulder-clay. Great abrasion of rocks there was undoubtedly. Blocks and 

 pebbles under the ice I saw in abundance, all grinding, and many of them scoring 

 the rocks. Much sediment there was, flowing out from under the ice. But what 

 became of this sediment ? It was carried off into rivers and lakes, there to form 

 beds of mud or sand — none having any resemblance to boulder-clay. The terminal 

 moraines of glaciers, no doubt, resembled it in one feature — want of stratification ; 

 but the absence from these moraines, of clay, hard, tough, and compact, showed 

 that the deposits were essentially different. 



It is no small confirmation of my own testimony on this point, that Agassiz, 

 when he visited Scotland to search for the signs of ancient glaciers, avowed that 

 he had never seen boulder-clay before he saw it in Scotland.* 



2. The next difficulty with which the glacier theory has to contend is, the 

 prevalence of boulder-clay in districts where it is scarcely possible to suppose 

 that glaciers could have existed, or, if they did exist, could have had to do with 

 the production of the deposit. 



Thus, in the flat districts of Norfolk, and in the still flatter districts of 

 Denmark and North Holland, boulder-clay is found. But there are no moun- 

 tains in or near these districts, where any glaciers could have been formed. The 

 same remark has been made by Mr Cumming of the boulder-clay in the Isle 

 of Man.f 



Even in those parts where there are both boulder-clay and mountains, as in 

 the Highlands of Scotland, it appears that the boulder-clay is derived from a 

 quarter the very opposite from that where a glacier may have existed. Along 

 the coasts of Western Ross-shire and Caithness, this deposit abounds, and has been 

 studied by Mr Jameson of Ellon and Dr Robert Chambers — both of whom at 

 first advocated the theory, that its formation could be accounted for by glacier- 

 action. Mr Jameson says — " The distribution of this dark grey mud harmonises 

 with the supposition that the transport of it has been from the N.W.; and a 

 movement of ice, from the N.W. to the S.E. across Caithness, is totally at variance 

 with the notion of the scratches having been caused by glacier- action proceeding 

 from the interior of the country towards the present coast." X And he adds in a 

 footnote, that the phenomena " indicate a movement of ice from the N.W., 

 where there is now nothing but open sea for an immense distance," and "all 

 suggestive of marine conditions." 



3. The next difficulty to the glacier theory is suggested by the immense 



extent of earth's surface over which the transporting agent has moved in one 



and the same direction. 



* See Edin. Phil. Journal for 1842, p. 227; and Geological Researches, by Jam£S Smith 

 of Jordanhall, p. 12. 



t " Isle of Man," by Cumming, p. 248. 



J Proceedings of the Geological Society of London for 1866, p. 269. 



VOL. XXV. PART II. 8 I 



