Dr Martens on the Glaciers of Spitsbergen. 173 



tain, there often exists an interval, a small valley, the hottom 

 of which is occupied by a small rivulet. The great glacier of 

 Bell Sound was separated from each of the lateral chains which 

 confined it by one of these valleys. On the north of the ter- 

 minal glacier of Magdalena Bay, a rivulet ran between the 

 moraine and the mountain. Those of the Entree and Pointe 

 aux Tombeaux supported themselves on both sides on the sur- 

 rounding mountains, except at their lower extremity, which 

 advanced a little beyond them. 



The travellers who preceded us have not directed their at- 

 tention to the blocks of stone which may be found on the sur- 

 face of these glaciers. The following are the observations I 

 made on this subject. 



The principal glacier of Bell Sound was soiled with earth 

 only at its sides. Those of Magdalena Bay were both cover- 

 ed with stones at their lower extremity. These stones occu- 

 pied nearly the eighth part of the breadth of the terminal 

 glacier ; but there were none in the middle, either of this 

 or of any other. Not cnly are blocks observed on their upper 

 surface, but they are likewise found embedded in the ice. I 

 have remarked a pretty considerable number of them over all 

 the height of the two lateral walls of the two principal glaciers 

 of Magdalena Bay, but never could I discern any on the face 

 looking to the sea. I cannot believe that any such exist, for 

 I have passed entire hours before the glaciers of the two bays 

 which we visited in order to make experiments on submarine 

 temperatures. I could thus see a great number of sections, 

 comprehending the entire thickness of the glacier, as the lat- 

 ter by degrees broke down into the sea. In order to assure 

 myself of the fact, I went in a boat to the glacier of Magda- 

 lena Bay, and entered into the little creeks formed by the 

 breaking down of the ice, and nowhere could I see blocks nor 

 even sand in the thickness of the ice ; every where it was per- 

 fectly pure and transparent. Before passing on to the expla- 

 nation of these facts, let us first examine comparatively how 

 the erratic blocks appear on the glaciei'S of Switzerland. 



All geologists agree in affirming, that no blocks are seen on 

 (he surface of the upper glaciers (Firne). Doubtless a few 

 insulated blocks may appear by chance, which have rolled down 



