84 M. Renoir on the Traces of Ancient Glaciers. 



Spitzbergen) t/iei/ never saw blocks transported by floating 

 tnasses of ice ;* and M. Eugene Robert, his colleague, states 

 that only once, at one o'clock on the morning of 18th July 

 1838, every one on board the corvette La Recherche saw 

 floating ice covered with pebbles andsand.\ However, in these 

 regions, according to the report of M. C. Martens, the coasts 

 are formed of steep rocks, against which the sea floats in sum- 

 mer. Every year some of these rocks necessarily fall, parti- 

 cularly at the time when the ice begins to melt, and a great 

 quantity of blocks and fragments of rocks are thus strewed on 

 the still frozen surface of the sea. A kind of breaking up of 

 the ice takes place every spring, and the numerous masses 

 then set afloat must convey all these blocks to a distance. 

 How comes it to pass, then, that none of them are seen % It 

 is undoubtedly because the enormous weight of these masses 

 of rocks, scattered at hazard over the icebergs, inevitably gives 

 an inclination to their surface which causes the blocks to slide 

 into the sea. Besides, the icebergs, while floating, often come 

 into collision with each other, and the shock which thel^locks 

 receive tends to produce the same result. In order to explain 

 the transportation of erratic blocks by floating ice, M. Eugene 

 Robert has recourse to the hypothesis that, at this epoch, the 

 ocean covered almost all the north of Europe. It must needs have 

 been the case, likewise, that, at the same period, a sea extended 

 over the south, and another over Algiers and Atlas, where 

 M. Le Blanc has recently ascertained the existence of abun- 

 dance of blocks. However, we know that none of the depo- 

 sits of this period have a marine character. And could the 

 seas, moreover, bordering on the tropics, be likewise traversed 

 by floating icebergs ? This latter hypothesis brings us back to 

 the subject of a universal ice. 



M. Robert has observed that primitive blocks, rolled and 

 rubbed, are collected in great numbers on the left bank of the 

 Neva, where it issues from the lake Ladoga, and on the margin 

 of the lake, at the same point, but none are to be seen on the 

 opposite bank. We are of opinion that this disposition of the 

 blocks is owing to their having been deposited by glaciers an- 

 terior to the formation of the lake and river ; in a word, that 

 they are nothing else than a moraine which has directed the 



* Bulletin de la Societe G^ologique de France, t. xi. p, 288. 

 t Ibid. p. 209. 



