Vol. 52.] GLACIAL GEOLOGY OF AHCTIC EUROPE, ETC. T'^O 



down on the floe. The undersides of these blocks came up covered 

 with mud and detritus from their contact with the bottom, and 

 were swept onward by the ice-pack, their black colour being very 

 distinguishable on the white surface of the ice-stream. Now, to 

 force these blocks of ice, which were probably 8 to 10 feet in 

 thickness, over an obstacle must require immense pressure, and it 

 seems unreasonable to suppose that they do not exercise some 

 abrading force; if not, why should the blocks have their under 

 surfaces coated with material from the bottom ? What I saw 

 occurring at Kolguev on a small scale has doubtless been carried on 

 extensively oft the coast of Novaya Zemlya. Given a comparatively 

 flat tract under water, such as Gooseland was, and a constant 

 process of emergence, I see no reason why floating ice moving with 

 a hundredfold greater velocity than a glacier should not be able to 

 wear down ridges over which it passes, provided that the process of 

 secular elevation is bringing the land and the floating ice into 

 contact. The formation of boulder-clay, replete with mollusca, 

 would be the natural sequence. 



Next let us turn to a more distant part of the Polar area, where 

 the powers of floating ice are witnessed on a much grander scale. In 

 Smith Sound the fragments of the heavy floes of the Palaeocrystic 

 Sea are summer and winter endeavouring to work their way south- 

 ward. Much of this ice is of stupendous thickness, floes 40, 50, and 

 even 100 feet thick being met with. This vast body of ice, ever 

 moving slowly southward through the strait, pushing over shallows, 

 and rubbing and grinding against the shore, must surely be gifted 

 with some wearing force. At headlands, or where the progress of 

 this pack is interfered with, the enormous power of floating ice is 

 exemplified. At such a point of pressure, the ice pushing against 

 the shore exerts extraordinary force. An enormous mass of floe is 

 brought to a stop against some part of the shore, while the check is 

 transmitted to the ice pushing behind. The edges of these various 

 floes are brought into contact with one another ; they rise at 

 their edges and crumble upon themselves, forming ridges of pressed- 

 up hummocks 50 to 60 feet high. The pressure from behind forces 

 the grounded floe to act in a similar manner against the shore. 

 Slowly, as if urged by some hidden hydraulic force, the edge, 

 impinging against the shore, commences to rear itself up in a chaos 

 of ice-debris, and the blocks roll down on the floe or on to the shore. 

 The portion that has grounded or been jammed against the shore 

 being now pulverized, the obstruction is cleared, and the ice 

 resumes its onward march. Is it possible that such pressure 

 between land and floating ice can take place without some effects 

 being produced? I think not, for at such points of contact, when 

 we were able to reach them, we found the rock polished. 



There arc two or three islands lying along the eastern shore of 

 Grinnell Land in Smith Sound, which offer some useful testimony, 

 notably Norman Lockyer Island, which is encircled by several well- 

 defined terraces or sea-beaches to an altitude of 300 feet. These 

 terraces rest on rock-surfaces which show in places, where they are 



