244 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



ice caps will appear, extend their glaciers down to the sea, and send 

 out their armadas of icebergs. To melt them enormous quantities 

 of the heat reserve of the sea will be consumed. Cold water forms 

 extensive superficial layers, and gradually fills the depth of the 

 ocean right to the Equator. 



6. The greater the ice caps grow, the more ice is bound in them 

 which otherwise would run as water back to the sea. Consequently, 

 its surface falls. Tylor ^ drew attention to this as early as the year 

 1868, and since then it has been discussed by many scientists. Nan- 

 sen^ has lately treated the question in detail. According to him, 

 the surface of the sea would rise 1 meter, if the now existing 

 glaciated areas were melted to an average depth of 24 m., and at the 

 maximum of the Quaternary glaciation (altogether 50 million km,- 

 average thickness 1,000 m.), the land ice contained so much water 

 that the sea may have been at least 130 m. shallower than it is to-day. 

 Nansen has made in his calculations very moderate assumptions of 

 the extension and thickness of the ice caps. Double the supposed 

 thickness and more does not seem to be improbable. As we see, there 

 must have been considerable changes of the sea level by this cause, 

 and it is obvious, that with such a sinking of the sea, the snow line 

 and the glaciers also must have moved downward. 



Thus, miothermic conditions and ice ages are established as a con- 

 sequence of orocratic relief. 



If we now imagine the relief pediocratic, we shall find not only 

 that the conditions producing glaciation and miothermic climate no 

 longer exist, but also that the climate must have been pliothermic, 

 much warmer than at present. 



Even in the Arctic regions, the snow line lies at considerable 

 heights above the sea level. This was the original condition also 

 on the Antarctic continent, where the now existing snow line at the 

 sea level has resulted from the active cooling eflfect of the huge gla- 

 ciated land and the passivity of the cooled sea. This proves that, 

 when the continents are peneplained, as assumed, they in no place 

 reach up to so high a level that perennial snow could be formed and 

 ice caps cover them. The disadvantageous effect which glaciation 

 has on the climate, fails. Heat is not taken from the atmosphere to 

 melt ice, nor from the hydrosphere, for there are no longer any ice- 

 bergs in the sea. Cold water does not extend over the surface of the 

 sea at high latitudes, and the cold water in the depths receives no 

 addition, but the oceans are gradually heated to ever greater depth, 

 and the surface layer of warm water grows thicker and warmer. 

 The sea currents and winds bring more heat from the low latitudes to 



• Alfred Tylor, " Evidence and Cause of Great Changes of the Sea Level During the 

 Glacial Period " : Geol. Mag., Vol. V, 1868, p. 576. 

 » Loc. cit, pp. 229-238. 



