Dr. J. W. Spencer — Subsidence versus Olacial Dams. 271 



In the east, the history of the changes has not been fully de- 

 ciphered. Erratics occur on the top of Mount Washington to 

 6300 feet, whilst on the top of Mount Katahdin, in Maine, they 

 occur to only 4400 feet (Upham), Conforming with Dr. Dawson's 

 views, as applied to the west, we have a greater rise in the White 

 Mountains than eastward. The altitude of beach formation in the 

 highlands of Labrador (1500 to 2000 feet) shows the recent uplift 

 to have been less than in New England. 



Combining the movements of the east and the west, it would 

 appear that the great Pleistocene uplift reached its maximum along 

 a line between the Gulf of the St. Lawrence and Vancouver Island, 

 rather than in higher latitudes. The youthfulness of the northern 

 topographic features shows that the elevation of the lands in the 

 higher latitudes, above the base-level of river-erosion, has taken 

 place in recent geological times ; for there is a lack of such great 

 carions in the country to the north of the great lake zone, as occur 

 in the region to the south of it. 



If the subsidence of the northern portion of the continent appears 

 to have been great, that of Barbadoes to the south-east appears to 

 have been greater, for Messrs. J. B. Harrington and A. J. Jukes- 

 Browne,^ have pointed out that there are on the island oceanic 

 deposits resting upon beds of sandstones and shales of probable 

 Miocene age, and beneath coral formations of age not greater than 

 the Pleistocene. These deposits indicate an origin of not less than 

 a thousand fathoms, and, as Mr. Jukes-Browne points out, probably 

 of vastly greater depth. This geologically recent subsidence was 

 likely to have been synchronous with that of the north, but may 

 have been one of those alternating conditions hypothecated by 

 Dr. Dawson. 



The fjords of the coast of Norway show that the Scandinavian 

 peninsula stood 4000 feet higher than now. The silts and terrace 

 deposits at 3000 ^ feet point to a subsidence of that region, the same 

 as similar deposits in the mountains of America. 



The deep submerged channels south of Asia, like that of the 

 Ganges, which is 3570^ feet deep, point to a recent submergence to 

 that amount. But such deep channels are not known in the north 

 of Asia, consequently the higher latitudes do not show a great 

 amount of recent depression. The Pliocene deposits of Sicily, at 

 3000 feet, demonstrate a recent elevation. 



Pliocene deposits in the south-east of England are now found at 

 600 feet above tide. Their counterparts at Utrecht have been shown 

 by Mr. Clement Reid to be now submerged more than 1143 feet.* 



The oft-quoted Moel Tryfaen deposits, in north-western Wales, 

 contain marine shells at 1400 feet, with similar but unfossiliferous 

 beds rising to nearly 2000 feet. These deposits, which I have 

 visited, I consider to have been formed where found. But they do 



1 Geology of Barbadoes, 1890. 



2 " High-Level Terraces of Norway," by J. R. Dakyns, Geol. Mag. 1877, p. 72. 



3 Brit. Admiralty Cbart, No. 70. 



* "Nature," August 12, 1886, p. 342. 



