T. F. Jamieson — Oscillation of Land in Glacial Period. 401 



of gravity of the earth to some degree, and thereby to cause a sensible 

 change in the sea-level, I shall here mention a few objections that 

 present themselves to the application of this theory made by Dr. 

 Croll. 



1st. The evidence of submergence we find in the shape of raised 

 sea-beaches, and beds of clay and sand containing marine fossils, 

 seems to show that during the time of their formation no such im- 

 mense cap of ice could have existed in the North Polar area, nor in 

 any of the glaciated regions of the northern hemisphere with which 

 we are acquainted. These elevated marine beds have been traced 

 by the Arctic Expeditions along the shores of Greenland and Grinnell's 

 Land ujd to lat. 82°, within a few hundred miles of the Pole itself, 

 proving that during the time they were laid down no great ice-cap 

 could have existed there, and showing that even in Greenland much 

 of the coast was covered with sea- water and not by ice. Again, in 

 Norway and Sweden the marine glacial beds show that during the 

 time of their formation, the land-ice in Scandinavia was much cir- 

 cumscribed, and had retreated far within the present line of shore. 

 In oiir own country also the Arctic shell beds found in Wales, 

 Tjancashire,^ and various parts of Scotland and Ireland, demonstrate 

 that the ice had shrunk into comparatively small dimensions, and 

 did not cover anything like the present area of the British Isles. The 

 same holds good in America, where the marine clays and sands 

 found along the banks of the Ottawa, the St. Lawrence, Lake 

 Champlain and Labrador afford convincing proof that the great 

 Canadian glacier had dwindled into comparative insignificance at 

 the time they were deposited. I am therefore unable to see where 

 the enormous mass of ice could have lodged that Dr. Croll calculates 

 upon ; for during the time of submergence to which these marine 

 beds belong the land-ice of the northern hemisphere, instead of 

 being at its maximum, was so far reduced as to be evidently inade- 

 quate for the purpose he requires. The submergence according to his 

 theory must have diminished step by step with the diminishing ice ; 

 for the action of gravitation he invokes operates instantaneously, and 

 the submergence could not have endured a day after the ice vanished. 



2nd. If the submergence was caused by an ice-cap drawing the 

 ocean northward, the sea-water should have risen to equal heights 

 along the same parallels of latitude, but the facts hitherto reported 

 do not agree with this at all, for they indicate a very unequal 

 amount of submergence in places situated in the same latitude. 

 The best-known high-lying marine beds of New England and 

 Canada lie between lat. 44° and 52°, which corresponds to that of 

 France and the South of England, just where evidence of submer- 

 gence is conspicuous by its absence. Again, we find in Scandinavia 

 evidence of submergence to the extent of 600 or 700 feet, but in the 

 same latitude along the eastern side of the Baltic and in Finland 

 no evidence of a like submergence has been found. In the neigh- 

 bourhood of Dublin, Lancashire and North Wales, sea shells are 

 found in the superficial beds of sand and gravel to heights of 1200 

 1 Macclesfield, Cheshire, see Geol. Mag. 1865, Vol. II. pp. 293-299. 



DECADE n. — VOL. IX. NO. IS. 26 



