SS4 



situ, into blocks of the same forms and dimensions as the erratics of 

 the Baltic. I remarked this particularly in Ostrogothland, near Lake 

 Roxen. Whether this Assuring of the rocks has been due to earth- 

 quakes, or the expansive power of ice in northern regions, or to what 

 other causes I cannot pretend to decide ; but reefs of such jointed 

 rocks before they emerged from the sea might have afforded an in- 

 exhaustible svipply of detached fragments, over and around which 

 the ice wovild freeze in winter. One block after another might be 

 buoyed up and floated off on the rise of the Baltic when the snows 

 melted, or of the ocean during high tides. 



It has been suggested that large blocks may have been pushed 

 far over the bed of the sea and over the land by a succession of 

 waves raised by earthquakes or by hurricanes. Without denying 

 that such agency may explain some facts in geology, I may remark 

 that we cannot be too much on our guard against assuming violent 

 catastrophes where the effects may have been brought about tran- 

 quilly, and even with extreme slowness. Let us imagine, for ex- 

 ample, a sunken reef of granite in Baffin's Bay, in about 75° north 

 lat., divided into fragmentary masses as above described, and these 

 masses becoming year after year involved in packed ice. In a few 

 months they may be drifted more than 1800 miles to the southward, 

 through the Straits of Belleisle, to the 48° north lat., the ice mov- 

 ing perhaps at a slow rate — no more than a mile an hour. We 

 might even land upon such ice-fields and be unable to determine 

 whether they were in motion or not. After a repetition of these 

 operations for thousands of years, the uneven bed of the ocean far to 

 the south may be strewed over with drift fragments which have 

 either stranded on shoals or have dropped down from melting bergs. 

 Suppose the floor of the ocean where they alight to be on the rise as 

 gradually as the bottom of the Baltic in our own times. The change 

 mav be so insensible that pilots may suspect, and yet scarcely dare 

 to insist upon the fact till its reality is confirmed by the experience 

 of centuries. At length a submarine ridge, covered with the tra- 

 velled fragments, emerges, and first constitutes an island, which at 

 length becomes connected with the main land, — in time, perhaps, 

 the site of a university like Upsala. Here the question is agitated 

 whether the land is stationary, or continually rising beneath their 

 feet. Perchance they decide that it is motionless, and yet it con- 

 tinues to move upwards, " E pur si muove," till by a growth as im- 

 perceptible as that of the forest tree, what was once a submarine 

 reef becomes the summit of an inland mountain. Here the geologist 

 admires the position, number, and bulk of the transported fragments ; 

 identifies them with the parent motmtains, a thousand miles distant 

 to the north ; and in speculating on the causes of the phsenomena, 

 imagines mighty deluges and tremendous waves raised by the shock 

 of a comet, or the sudden starting up of a chain like the Andes out 

 of the sea, by which huge rocks were scattered over hill and dale 

 as readily as shingle is cast up by the breakers on a sea beach. 



But it is time to return from these digressions and to consider the 

 other memoirs treating of these and similar subjects which have 



