MECHANICAL ACTION OF GLACIEES. 159 



at this time the Baltic communicated with the White 

 Sea. 



It is alleged that it was after the melting of the con- 

 tinental ice, and while the glaciers were thus receding from 

 their extension to the valleys, to the summits and elevated 

 ridges, where they still maintain their position, that the 

 transition issuing in the existing state of the country 

 occurred. At about the same period the communications 

 between the Baltic and the White Sea were interrupted, 

 and the ground of the Scandinavian peninsula, in the 

 southern part of Norway, was elevated about 160 metres, 

 or 530 feet. Old shore lines, banks of marine shells, and 

 sand terraces, supply indications, both in Norway and 

 Sweden, of this having been the case, and prove at the same 

 time that the elevation varied with time ; and that during a 

 lengthened period it was a time of stagnation, perhaps even 

 of subsidence. In Norway there exist banks of marine 

 shells at, at least, two different altitudes, the one about 

 150 metres, or about 500 feet, the other about 300 metres 

 or 1000 feet, above the present level of the sea. With 

 the origin of these heaps of shells we have not at present 

 to deal ; it is their position alone which here concerns us. 

 The higher-lying banks contain Arctic shells ; the lower- 

 lying ones northern shells, corresponding to the species 

 which live at the present day along the coast. Consider- 

 ing both to have been collected on the shore of the ocean 

 the upper heaps in days more remote, the lower ones in 

 days nearer to our own, these heaps supply indications at 

 once of an elevation of the land, and of the other pheno- 

 mena referred to in connection therewith. In our own 

 time the coasts of Sweden, on the Baltic, are supposed 

 to be rising at the rate of a metre, or forty inches, in a 

 hundred years. 



Old moraines exist at a succession of altitudes up to 

 that of those which are being formed under our eyes 

 sometimes lying across the depth of the valley, terminal 

 moraines ; sometimes along the line of the water-courses, 

 lateral moraines. Large moraines exist on the two sides of 



