170 SCIENCE IK SHOUT CHAPTERS. 



the base of the highland mountains to the low-lying districts 

 beyond, that we meet with any considerable deposits of stony 

 clay. The higher districts of the Southern Uplands are almost 

 equally free from any covering of till." 



This description is precisely the same as I must have written, 

 had I so far continued my imaginary sketch of the results of 

 ancient glaciation as to picture what must remain after the 

 glaciers had all melted away, and the sea had receded suffi- 

 ciently to expose their submarine deposits. 



Throughout the above I have assumed a considerable sub- 

 mergence of the land as compared with the present sea-level on 

 the coasts of Scotland, Scandinavia, etc. 



The universality of the terraces in all the Norwegian valleys 

 opening westward proves a submergence of at least 600 or 700 

 feet. When I first visited Norway, in 1856, I accepted the usual 

 description of these as alluvial deposits ; was looking for glacial 

 vestiges in the form of moraines, and thus quite failed to ob- 

 serve the true nature of these vast accumulations, which was 

 obvious enough when I re-examined them in the light of more 

 recent information. Some few are alluvial, but they are ex- 

 ceptional and of minor magnitude. As an example of such 

 alluvial terraces I may mention those near the mouth of the 

 Komsdal, that arc well seen from the Aak Hotel, and which a 

 Russian prince, or other soldier merely endowed with military 

 eyes, might easily mistake for artificial earthworks erected for 

 the defence of the valley. 



In this case, as in the others where the terraces are alluvial, 

 the valley is a narrow one, occupied by a relatively wide river 

 loaded with recent glacial debris. It evidently filled the valley 

 during the period of glacial recession. 



The ordinary wider valleys, with a river that has cut a nar- 

 row channel through the outspread terrace-flats, display a 

 different formation. Near the mouth of such valleys I have 

 seen cuttings of more than a hundred feet in depth, through an 

 unbroken terrace of most characteristic till, with other traces 

 rising above it. This is the ordinary constitution of the lower 

 portions of most of the Scandinavian terraces. 



These terraces are commonly topped with quite a different 

 stratum, which at first I regarded as a subsequent alluvial or 

 estuarine deposit, but further examination suggested another 

 explanation of the origin of some portions of this superficial 

 stratum, to which I shall refer hereafter. 



Such terraces prove a rise of sea or depression of land, dur- 



