AND THE REINDEER IN MIDDLE EUROPE. 347 



effect. But where surfaces abraded by the glaciers show themselves under the 

 present sea the water must certainly have once stood at a lower level, for the 

 ice descends not beneath the plane of the sea, but is melted and undermined by 

 the latter, as is witnessed in the case of the polar glaciers, under which explor- 

 ers have found it practicable to penetrate at ebb tide to considerable distances.* 



The sea meantime climbed upwards, the land became warmer, the general 

 ice-envelope melted, the loftier ridges came to light, while the glacial mass sep- 

 arated into isolated ghaciers which filled the valleys to their mouths. Now, first 

 occur distinct moraines, as in the glaciers of to-day, lateral moraines, tenninal 

 moraines, ramparts of rock heaped in tines, of which the outermost stretch to the 

 present coast, while the innermost rise to a certain height on the walls of the 

 valleys, or form baniers across them, where they denote the halting point of the 

 retreat before the sea. The sea followed to the height of some 500 feet, for at 

 this elevation are found banks of shells containing mollusks which belong to the 

 Arctic ocean. At the same time the mighty masses of ice, as they melted, gave 

 forth streams which, dammed up here and there by the terminal barriers of the 

 glaciers, formed inland seas, while the fine material, which all glacier currents 

 bear along with them in great quantities, settled down in the form of clay, marl, 

 and sand. The ocean on the one side, the inland waters on the other, plied 

 their work of erosion on the older masses underlying the ice envelope ; the gla- 

 ciers continued to bring down erratic blocks which, after being long chari- 

 oted on their icy vehicle, finally sank on the sites where we now find them. 

 And thus was gradually brought about the geological period, in which the gla- 

 ciers extend only at a few places to the sea, or else impend at a considerable 

 height above its level, while in the bosom of the valleys reigns, for the most 

 part, a mild and genial climate. 



This prehistorical glacier period of the north is no romance ; its consistency 

 with observed facts is undeniable. The series of these facts is thus given by M. 

 Kjerulf : 



What do we find to be the prevailing arrangement among these glacial masses piled up 

 and distributed by the sea? Undermost, where they could not again be subjected to the 

 action of water, sand, and rolled stones, that is to say, scoured sand and stones. In these 

 we have the material which was moved forward under the pressure of the ice over the face 

 of the rock. Would we learn the direction of the scouring process, it is to the blocks thus 

 moved that we must have recourse. As these are mostly broken to pieces, small and rounded, 

 they have been called "rolled stones,"' though this, strictly speaking, is an improper name, 

 and they might more properly be called "scoured stones." They have not been rolled, but 

 have been reciprocally crushed by one another, and fixed in the ice, like the diamond in the 

 gravers burin, they have traced furrows and striae in the subjacent rock. Above the scoured 

 sand banks of rolled stones lie the difi"erent sorts of loam ; first, calcareous loam, marl loam ; 

 in precincts open to the waters of the glaciers, sedimentary lime and loam brought down 

 from the silurian strata ; next shell loam generally, where the elevation was not too great or 

 the currents of cold, fresh water, produced by thawing, not too powerful ; then brick earth, 

 without shells, referable perhaps to an age when the inundation of the interior country was 

 at its highest ; then sand, and on the top of all sand loam. 



The great erratic blocks first occur above the beds of scoured stones, loam, 

 and sand; in Scandinavia they have been brought into the position in which we 

 now find them in some instances by cakes of floating ice, btit for the most part 

 by the glaciers themselves. 



We have thus a long tract of time before us, during which a state of things 

 like that now existing in Greenland prevailed, and an icy ocean washed the 



* The statement given by Sir Charles Lyell, in his Geological Evidences of the Antiquity 

 of Man, varies in some respects from the views of the text: "When these masses of ice 

 reach the friths of Greenland they do not melt or break up into fragments, but continue their 

 course in a solid form under the salt water, grating along the rocky bottom, which they 

 must polish and score at depths of hundreds, and even of more than a thousand feet. At 

 length, when there is water enough to float them, huge portions, having broken off, fill 

 Baffin's bay with icebergs of a size exceeding any which could be produced by ordinary 

 land glaciers." (Chap, xiii.) 



