136 Correspondence — D. Mackintosh. 



Passing by the inconsistency attributed to Dr, Dawson in con- 

 nexion with the scooping out and partial filling up of the Canadian 

 lake-basins (an inconsistency, I believe, not to be found in the work), 

 I would confine attention to the question of marine drift versus 

 moraines. 



Dr. Dawson evidently refers to sea-beaches and sea-beds as they 

 existed during a period of floating ice, when many of the resultant 

 phenomena were very different from those with which we are now 

 familiar around the coasts of the British Isles. Few men. I should 

 supj)ose, are better acquainted with the forms of the accumulations 

 now produced by marine-glacial action along the coasts of British 

 North America, and therefore he must be well qualified to trace the 

 origin of similar accumulations in more or less inland districts. 

 Neither ought we to forget that in referring drift phenomena to 

 causes now operating in the neighbourhood, instead of invoking a 

 catastrophical order of nature. Dr. Dawson is illustrating the great 

 Lyellian principle on which the progress of geology during the last 

 forty years has mainly depended. Dr. Dawson admits the former 

 southerly extension of Grreenlandic conditions, but he does not forget 

 that even around Greenland the sea and floating ice are now giving 

 rise to phenomena similar to many of those associated with Canadian 

 drift-deposits. 



When the accumulation of the Boulder-clay of Canada was first 

 attributed to land-ice, geologists were ignorant of many facts revealed 

 by extensive railway cuttings which would seem to point to deposi- 

 tion under water. 



Most of the so-called moraines of Canada occupy positions in which 

 they could never have been left by glaciers, while in form and 

 structure they differ from any actual moraine with which we are 

 acquainted ; and as the tendency to call every drift mound a moraine 

 still lingers among many of our younger geologists, the following 

 statement of facts may not prove altogether useless. 



Principal Forbes (as I have already noticed in this MaGx^zine) 

 asserted that the actual Swiss moraines never contain smoothed or 

 polished stones like those characterizing what in his day was called 

 diluvium. 



Sir Charles Lyell, in his Antiquity of Man, states that in the present 

 moraine of the Ehone only one stone in several thousand is glacially 

 polished and scratched, and that in the case of fragments of ser- 

 pentine and limestone in the moraines of Zermatt, etc., only one in 

 several hundred is glaciated. 



Professor Eamsay has repeatedly observed that it is sometimes 

 impossible to distinguish moraine matter left on the land from 

 moraine matter deposited in the sea. 



According to Professor Nordenskiold (see recent articles in the 

 G-EOL. Mag.), moraines are scarcely ever met with in Greenland; 

 and it has been stated by eminent Scandinavian geologists that 

 extinct moraines are rare in Sweden. 



The Eev. M. H. Close and Mr. Kinahan, in their most elaborate 

 pamphlet on the Glaciation of lar-Connaught, believe that the rarity 

 of traces of local glaciers in Ireland is an indication thai the mo\'e- 



