GLA CIA L S UCCESSION IN NOR IVA V. I 3 3 



way in epiglacial time was very like a modern map of Green- 

 land. The isotherm of o°C. for the year must have followed the 

 southern coast perhaps as far up as to the polar circle. The 

 lower isotherms must have enclosed a pronounced minimum to 

 the east of the ice shed, where certainly — 20°C. must have 

 reigned.^ While the difference from the present mean tempera- 

 ture at the" coast was only 5 to 6° C, the difference near the pole 

 of maximum cold must have been 15° C. at least. This great 

 difference, which is a necessary consecjuence of the contrast 

 between coast climate and the pronounced continental climate 

 over the east side of the great ice field, is as yet not sufficiently 

 noted by the students of glacial time. An exact consideration 

 of the distribution of the meteorological elements above the 

 inland ices will give the solution of many glacial problems. I 

 shall here only remark that the snowfall in this continental 

 region must have been almost imperceptible as in winter in 

 Siberia now — and likewise the melting. Now, the power which 

 keeps the glacier in motion is ever the surplus of snowfall. The 

 whole continental side of the inland ice must thus be kept in quite 

 a passive motion, be pushed as a rather thin ice plate out to the 

 margin by the press from the greater snowfall on inside ice nearer 

 the ice shed and the coast. The reliable measures of the ice 

 sheet in the Baltic show really very small dimensions — less than 

 200 meters- — thus it will become intelligible why the greater ice 

 masses to the west can keep the ice divide four to six times nearer 

 the western margin. An ice plate of about 100 meters or less 

 must be impotent to erode. The bottom moraine from the more 

 powerful inner part must be gradually built up de/o2V the outer 

 thin marginal ice sheet. On the continental side we will have 

 formed a regular boulder-clay or thick bottom moraine outside 

 an area where denudation in the form of broad shallow basins or 

 plains will still take place — all this against the deep rock basins 

 with terminal moraines and terraces before them, on the coast 

 side. The snowfall here will be very great. The surplus ice 



'Cf. H. Mohn's meteorological map of Greenland in Wissenschaftliche Ergebnisse, 

 von Dr. Nansen's, Durchquerung von Greenland, Gotha, 1892. 



