James Croll — On the Glacial Epoch. 309 



things as recorded by Hayes and by Nordenskiold affords us a 

 glimpse into the condition of things in the interior of the continent. 

 'J'hey both found by observation, what follows as a necessary result 

 from physical considerations, that the upper surface of the ice plain, 

 under which hills and valleys are buried, gradually slopes upioards 

 towards the interior of fJie continent. Prof Nordenskiold states that 

 when at the extreme point at which he reached, thirty geographical 

 miles from the coast, he had attained an elevation of 2200 feet, and 

 " that the inland ice continued constantly to rise towards the interior, 

 so that the horizon towards the east, north, and south, was termi- 

 nated by an ice-border almost as smooth as that of the ocean." 

 (Geol. Mag. 1872, VoL IX. p. 360.) 



Dr. Hayes and his party penetrated inwards to the distance of 

 about seventy miles. On the first day they reached the foot of the 

 great Mer de Glace, the second day's journey carried them to the 

 upper surface of the ice-sheet. On the third day they travelled 

 thirty miles, and the ascent, which had been about 6°, diminished 

 gradually to about 2°. They advanced on the fourth day about 

 twenty-five miles; the temperature being 30° below zero (Fah.). 

 " Our station at the camp," he says, " was sublime as it was danger- 

 ous. We had attained an altitude of 5000 feet above the sea-level, 

 and were seventy miles from the coast, in the midst of a vast frozen 

 Sahara immeasurable to the human eye. There was neither hill, 

 mountain, nor gorge, anywhere in Adew. We had completely sunk 

 the strip of land between the Mer de Glace and the sea, and no 

 object met the eye but our feeble tent, which bent to the storm. 

 Fitful clouds swept over the face of the full-orbed moon, which, 

 descending towards the horizon, glimmered through the drifting 

 snow that scudded over the icy plain — to the eye in undulating lines 

 of downy softness, to the flesh in showers of piercing darts." (Open 

 Polar Sea, p. 134.) 



Dr. Eink, referring to the inland ice, says that the elevation or 

 height above the sea of this icy plain at its junction with the out- 

 skirts of the country, and where it begins to lower itself through the 

 valleys to the friths, is, in the ramifications of the Bay of Omenak, 

 found to be 2000 feet, from which level it gradually rises towards 

 tTie interior. (Journ. of the Eoyal Geographical Soc. 1853, vol. xxiii.) 



Dr. Eobert Brown, who, along with Mr. Whymper in 1867, at- 

 tempted a journey to some distance over the inland ice, is of opinion 

 that Greenland is not traversed by any ranges of mountains or high 

 land, but that the entire continent, twelve hundred miles in length 

 and four hundred miles in breadth, is covered with one continuous 

 unbroken field of ice, the upper surface of which, he says, rises by 

 a gentle slope towards the interior. (" Physics of Arctic Ice," Quart. 

 Journ. Geol. Soc. for February, 1871.) 



Suppose now the point reached by Hayes to be within 200 miles 

 of the centre of dispersion of the ice, and the mean slope from that 

 point to the centre, as in the case of the Antarctic cap, to be only 

 half a degree ; this would give 10,000 feet as the elevation of the 



