228 WAREEN UPHAM, ESQ., ON CAUSES OF THE ICE AGE. 



geologists suppose to represent tlie glacial period, it would not 

 require a very great temperature if the thing went on gradually. 



Professor J. Logan Lobley, F.G.S. — Mr. Gooch expresses 

 his anxiety to know on what grounds the author of the paper 

 stated that there was no evidence in the Mesozoic, Tertiary 

 and Quaternary eras, of the sun's heat having been much less 

 than at present. I would go further and say that it appears 

 to me there is no evidence of the sun's heat having been much 

 less than now, even during the Paleeozoic times ; for I find the 

 same organisms in the Cambrian rocks as live at the present 

 time. The same genera are found in many formations living on 

 without more than specific change to the present time. That, I 

 think, is sufficient proof, apart from vegetable remains (which 

 afford strong evidence of the fact) that the sun's heat has been, 

 practically, unchanged from the earliest geological times to the 

 present. Mr. Tuckwell stated that the production of an enormous 

 quantity of snow round the North Pole must have required an 

 enormous amount of evaporation. That is true ; but is there not, 

 under present conditions, an enormous amount of evaporation ? It 

 is actually so in tropical portions of the globe. Supposing land to 

 be elevated 2,000 or 3,000 feet above its present level there would 

 be the conditions required to produce a greater condensation of 

 vapour in the atmosphere in the form of snow and less in tiie form 

 of rain. The normal snow line is a little more than 5,000 feet 

 above the level of the sea in the north part of the British Isles. 

 If the North Sea were turned into dry land with other geographic 

 changes, which would lessen the warmth of the Atlantic waters, 

 there would be a greater amount of cold in this country to produce 

 greater precipitation of snow, and the retention of that amount of 

 snow which produces the glacial conditions. But it might be 

 asked, " What is meant by the Ice Age ? " One means one 

 thing and another something different — one may mean the land 

 surface, at its present level north of the 50' parallel covered with 

 an ice cap, and another may mean the elevated regions only of 

 the northern hemisphere covered with great glaciers that glaciated 

 the lower portions of these regions, and not that the great plain, 

 extending far to the south, was covered Avith one great ice cap. 

 On the plains of Siberia and Alaska there is no evidence of 

 glaciation ; and we can only surmise that, by the rapid melting 

 of accumulated snow and ice, great floods may have been pro- 



