T. BELT ON THE DEIFT OF DEVON AND COENWALL. 85 



distribution of the surface deposits, I was not led to adopt it on 

 that account alone, but because, in addition, I found abundant evi- 

 dence that the ice from the north had moved down the bed of the 

 Atlantic, and from the direction of Greenland as its chief gathering- 

 point. Thus Newfoundland is glaciated from the north-east, and 

 the ice advanced up the valley of the St. Lawrence, and forced the 

 drainage from the great lakes to run into the basin of the Missis- 

 sippi. Even so far westward as the Lake of the "Woods, we learn 

 from Mr. G. M. Dawson's elaborate and instructive report, that the 

 ice moved persistently from the north-east*. The whole of Cape 

 Cod is a great moraine, proving that the bed of the Atlantic was 

 occupied by ice several degrees of latitude further south than is re- 

 quired on the European side of the basin to block up the English 

 Channel. 



In the Old "World I found that the ice had advanced upon Siberia 

 from the north, had overridden Iceland, the Hebrides, and the north 

 of Scotland from the north-west, and at the extreme south-west of 

 Ireland was 2000 feet thick. Mr. T. F. Jamieson has clearly shown 

 that the ice that glaciated Caithness came from the north-west, and 

 not from the south-east, as had been supposed by Mr. Croll. The 

 Shetland Isles are too small to have borne local glaciers ; yet we find 

 from the interesting observations of Mr. C. W. Peach that they are 

 hugely glaciated. On Lerwick he found the grooves and striae 

 pointing north and south, and that the drift had evidently come from 

 the north. In North Uist he found great ruts and scorings pointing 

 W.N.W. On reaching the top of Muckle Heog, 500 feet above the 

 sea, he found the W.N.W. end vertical and polished down to at least 

 150 feet from the top. To what agent can we ascribe the glaciation 

 of these islets, excepting an immense body of ice moving from the 

 north-west f ? 



Greenland is now covered with ice ; and this theory assumes that in 

 the Glacial Period ice advanced from that direction, and flowed furthest 

 down the deepest channel, which was the bed of the Atlantic. That 



* Report on the Geology of the region in the vicinity of the 49th parallel, 

 1875. Map showing Glacial markings. I am indebted to Prof. Hall for infor- 

 mation about Cape Cod. 



t For Caithness see Quart. Journ. Geol. Soc. vol. xxii. p. 261 ; and for the 

 Shetland Isles, Geological Magazine, 1865. So long ago as 1852, Dr. Robert 

 Chambers, in a remarkably able paper read before the Royal Society of Edin- 

 burgh, and published in full in the ' Edinburgh Philosophical Journal ' for 1853, 

 urged that the whole of the glaciation of Scotland could not have been produced 

 by ice gathering on the mountain-chains, as they themselves had been overrid- 

 den, and that the ice that had left the highest markings had flowed from the 

 north-west. He argued that both the hills and valleys, including the lake- 

 basins of Sutherland and Ross-shire were due to the erosion of the rocks by an 

 immense body of ice that had moved down upon Scotland from the north-west. 

 Mr. T. F. Jamieson, in his valuable papers on the Glacial Period, published in 

 the Journal of this Society, has also mentioned many facts pointing to a flow 

 of ice from this direction ; but Mr. James Geikie, in the otherwise very com- 

 plete account of the glacial phenomena of Scotland in his ' Great Ice Age,' has 

 not discussed this important question, though many of the facts mentioned by 

 him, such as the blocking-up of the Clyde valley, would receive an easy solution 

 by this theory. 



