in Scotland and Parts of England. 265 



derable hills, by one movement. This could never be done 

 by ice partially floating, or merely impelled by ordinary cur- 

 rents. While those who argue for the abrading powers of 

 icebergs, can scarcely adduce a single example of that 

 agency in nature, I can adduce negative facts of no small 

 force against such an agency. At the falls of the copious 

 river Glommen, in Norway, just above the cascade, the rock 

 is seen striated under the water, obliquely to the course of 

 the river. Now, this river must have upbreaks of ice every 

 spring, filling its channel at this place with a tolerable re- 

 presentation of the ice-floes in question ; yet no strise are 

 seen in that direction, and thousands of winters have failed 

 to obliterate the original glacial markings in any perceptible 

 degree. Many rivers of our own country have driftings of 

 broken ice impelled clown their channels with immense force 

 at the end of every great frost ; yet their rocky channels pre- 

 sent irregularities which give them a totally different appear- 

 ance from the abraded and striated surfaces. I was first im- 

 pressed with this objection to the ice-floe theory on observ- 

 ing some rugged, or only slightly blunted points of rock 

 starting up in the bed of the Tweed, near Peebles, where in 

 my early days I have witnessed magnificent examples of the 

 rush of river-ice so well described in Thomson's " Winter.'' 

 This ice is, as is generally known, often impeded by ground- 

 ing, and sometimes is carried gratingly over the channel of 

 the river exactly in the manner of the ice-floes of the ocean ; 

 and, though the phenomenon is on a comparatively small 

 scale, some memorials of abrasion might be expected, if ice 

 carried by water were really capable of leaving any beyond 

 the most trifling. 



As an example of what may be called inadequate theories 

 of the polished and striated surfaces, reference may be made 

 to one lately started in Ireland, where, as is well known, such 

 phenomena are fully as conspicuous as in Scotland. Mr 

 Kobert Mallet appears to be the real author of this theory, 

 though Colonel Portlock claims to have suggested something 

 similar about the same time. The main proposition is, that 

 a detrital covering of the land, raised along with it at the 

 time of elevation, slipped down its face into the sea, and even 



