718 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1908. 



the ability of the water, which had scoured the sides of these stones to such 

 au extent aud narrowed their bases, to carry away or erode the intermediate 

 bottom. We found similar " stone giants " near Slite of the same size and 

 height. 



This explanation of Linne as to the origin of these " raiikar " 

 is, as is well known, quite correct, and is fully recognized as such at 

 the present time. * * * 



To quote further from his lecture on the growth of the habitable 

 land : 



The two large mountains on Gotland, " Torsburg " and " Hoburg," have 

 perpendicular sides of limestone striated and hollowed out by wave action 

 when the sea covered all Gotland with the exception of these two rocks which 

 rose above the surface in the way that the " Charles Islands " do at the present 

 time. 



This observation is quite correct, as Gotland was at one time en- 

 tirely covered b}^ the post-glacial sea, from which it later rose. , 



Besides shore formations and the action of the sea on rocks Linne 

 also mentions the existence of large stone blocks, the size of which 

 caused him great wonder, but which he believed to have been trans- 

 ported by the waves from foreign shores : 



* * * * -» * * 



The " self-eroding stone," a block of stone lying 1 mile and a half north of 

 Hoburg, was so large that no human power could have carried it thithei", and 

 besides it was situated in the middle of the island or about midway between 

 the eastern and the western shore. This variety of stone was quite unusual in 

 that region, a circumstance which caused the peasants to urge us to inspect it, 

 believing that it contained some metal. The block was 3 yards high, 7 yards 

 broad, and scarcely 6 feet between the east and west sides; it was lying entirely 

 above the surface and consisted of red spar, resembling an Aland-stone, between 

 the grains of which appeared a black glimmer which shone like gold in the sun. 

 By constant exposure to the sun the southern side of this block had been made 

 so brittle that it seemed to consume itself, and the gravel which had fallen from 

 it formed quite a barrow all around, particularly on the south side ; hence this 

 stone was " self-eroding," and contained no ore. Since all saxa, or granite, is 

 formed underground, and since this block was entirely above ground in a place 

 where there was no higher land and where all else was limestone, it is difficult 

 to understand either its present position or whether the sea had been powerful 

 enough to roll it from Sweden or Russia at a time when this place was under 

 water. 



This block probably still exists and should by all means be ex- 

 empted from destruction, both because of its being unique as a natural 

 monument and because of Linne's remarks concerning it. * * * 



Thus Linne became the first to announce the existence of a block of 

 one of the " rapakivi " species on Gotland, rocks which have played 

 such an imj)ortant role in the study of the glacial drift. 



