James Geikie — On Changes of Climate, 63 



decided evidence in the Scottisli Till. The "stony clay" is un- 

 doubtedly the same deposit as our Till ; but it is possible that some 

 of the " sand and angular gravel," associated with the " Eulles- 

 teensler" of Scandinavian geologists, may represent No. 2 of the 

 Scottish section. The osar or asar agree precisely with our Karnes. 

 They are composed of water- worn detritus, gravel or sand, or both. 

 Sometimes the ingredients are fine, sometimes very coarse. Murchison 

 describes large tracts of northern Kussia as covered with wide 

 expanses of undulating sandhills ; and these occur also in Northern 

 Germany and in Denmark. Occasionally shells are obtained in this 

 drift ; those of the Danish drift being of the same species as now 

 occupy the adjoining seas. The same would seem to be the case 

 with some of the Swedish asar. Sir C. Lyell mentions the occur- 

 rence of a ridge of gravel near Upsala which showed a bed of marl 

 made up of the remains of " the mussel, cockle, and other marine 

 shells of living species, intermixed with some proper to freshwater." 

 Several huge erratics lay upon the top of this ridge. All the observers 

 agree that the dispersion of the large angular erratics took place after 

 the accumulation of the osar, for everywhere the big blocks rest upon 

 these hills of pebbles and sand, an appearance which is common to 

 Eussia, Germany, and Denmark, no less than to Scandinavia. Here, 

 then, the phenomena are precisely the same as we meet with in 

 Scotland, and the conclusion seems irresistible that the asar were 

 accumulated during a temperate condition of things, and while the 

 land was sinking, and that the erratics only began to be dispersed 

 from the Scandinavian mountains when the subsidence had become 

 considerable, and the glaciers consequent upon an increase of cold 

 had entered the sea. The clays with Arctic shells (No. 4) are the 

 representatives of the Scottish shelly clays ; and, like them, give 

 evidence of floating ice. The moraines (No. 5) are, of course, much 

 larger than their Scottish equivalents, but they tell exactly the same 

 story. 



The Glacial deposits of North America give a similar succession, 

 with the addition of some interesting details. And as these throw 

 considerable light upon the character of those changes that followed 

 upon the withdrawal of the great ice-sheets, I shall refer somewhat 

 more fully to the American drifts than I have done to the Glacial 

 deposits of Europe. 



The lowest Glacial deposit recognized by Canadian and American 

 geologists is " unstratified boulder-clay," or " unmodified drift." 

 In some places this deposit is found to overlie beds of sand, gravel, 

 and clay, and these beds have occasionally yielded vegetable remains. 

 Dr. Dawson cites ' the case of "a hardened peaty bed which appears 

 under the Boulder-clay on the north-west arm of the River of 

 Inhabitants in Cape Breton." " It contains many small roots and 

 branches apparently of coniferous trees allied to the spruces." In an 

 interesting paper by Mr. C. Whittlesey (Smithsonian Contributions), 

 reference will also be found to the occurrence below and in the 

 " unmodified drift " of decayed leaves and the remains of the Mas- 

 1 Acadian Geology, p. 63. 



