510 PROCEEDINGS OF COLUMBUS MEETING. 



and 1,500 feet or more, which lias been claimed by British geologists for northern 

 Wales, north western England and a part of Ireland, on the evidence of marine 

 shells and fragments of shells in glacially transported deposits, is shown by Belt, 

 Goodchild, Lewis and others to be untenable. Indeed, these fossils, not lying in 

 the place where they were living, give no proof of any depression of the land, since 

 they have been brought by currents of the ire-sheet moving across the bed of the 

 Irish sea. Bui it is clearly known by other evidence, as raised beaches and fossil- 

 iferous marine sediments, that large portions of Great Britain and Ireland were 

 slightly depressed under their burden of ice and have been since uplifted to a ver- 

 tical extent ranging probably up to a maximum of about 300 feet. 



In Scandinavia the valuable observations and studies of Baron de Geer have 

 supplied lines of equal depression of the land at the time of the melting away of 

 the ice. This region of greatest thickness of the European ice-sheet is found to 

 have been depressed to an increasing extent from the outer portions toward the 

 interior. The lowest limit of the submergence, at the southern extremity of 

 Sweden, is no more than 70 feet above the present sea-level, and in northeastern 

 Denmark it diminishes to zero; but northward it increases to an observed amount 

 of about SOI) feet on the western shore of the Gulf of Bothnia, near latitude 63°. 

 Along the coast of Norway it ranges from 200 feet to nearly 600 feet, excepting far 

 northward, near North cape, where it decreases to about 100 feet. In proportion 

 with this observed range of the subsidence on the coast of Scandinavia, its amount 

 in the center of the country was probably 1,000 feet. 



A very interesting history of the post-glacial oscillations of southern Sweden 

 has been also ascertained by Baron de Geer, which seems to be closely like the 

 post-glacial movements of the northeastern border of North America. As on our 

 Atlantic coast, the uplift from the Champlain submergence in that part of Sweden 

 raised the country higher than now. The extent of this uplift appears to have 

 been about 100 feet on the area between Denmark and Sweden, closing the entrance 

 to the Baltic sea, which became for some time a great fresh-water lake. After this 

 another depression of that region ensued, opening a deeper passage into the Baltic 

 than now, giving to this body of brackish water a considerably higher degree of 

 saltness than at present, with the admission of several marine mollusks, notably 

 TAttorina litorea, L., which are found fossil in the beds formed during this second 

 and smaller submergence, but are not living in the Baltic to-day. Thus far the 

 movements of southern Sweden are paralleled by the post-glacial oscillations of 

 New England and eastern Canada ; but a second uplifting of this part of Sweden 

 is now taking place, whereas no corresponding movement has begun on our Atlantic 

 border. It seems to be suggested, however, that it may yet ensue. The subsidence has 

 ceased or become exceedingly slow in eastern New England, while it still continues 

 at a measurable rate in New Jersey, Cape Breton island, and southern Greenland. 

 So extensive agreement on opposite sides of the Atlantic in the oscillations of 

 the land while it was ice-covered, and since the departure of the ice-sheets, has 

 probably resulted from similar causes, namely, the pressure of the ice-weight and 

 the resilience of the earth's crust when it was unburdened. The restoration of 

 isostatic equilibrium in each country is attended by minor oscillations, the condi- 

 tions requisite for repose being over-passed by the early reelevation of outer por- 

 tions of each of these great glaciated areas. 



In view of this harmony in the epeirogenic movements of the two continents 

 during the Glacial, Champlain, and Recent periods, it seems evident that the close 



