ADDENDA. 



623 



admitted by all that the grooves on the solid rock were formed by the 

 passage of these boulders over it. Although the minor inequalities of 

 the surface of the land appear to have had no influence whatever on the 

 action which produced the scratches, yet the larger features, as the 

 general bearing of the main valleys, appear to have determined their 

 direction. Sir James distinctly states that the scoopings and furrows have 

 precisely that form which the long action of torrents tends to produce on 

 a solid rock ; but he adds, and I believe most truly, that the furrowed 

 surface produced by such means is smooth, and not deeply scored and 

 scratched. It is indeed utterly inconceivable that large stones should be 

 carried along as if " independently of their gravity" by any ordinary means, 

 with such velocity, as to mark with horizontal lines the perpendicular 

 face of a rock. From these facts, — from the presence of great erratic 

 blocks, from the steepness of one face of the grooved hills, and the 

 tail of sediment stretching out from the other, Sir James Hall, having 

 in his mind the recorded cases of the great waves consequent on earth- 

 quakes, inferred that a vast deluge had burst over the country from the 

 westward. 



M. Brongniart, and lately M. Sefstrom (L'Institiit, February 22d, 1837), 

 have described phenomena in Sweden almost identical with those of Scot- 

 land. The rocks are there grooved and scratched,* even to the height of 

 1500 feet, in north and south lines, parallel to the valley of the Baltic and 

 of the Gulf of Bothnia ; but tliey are considerably (deflected by the 

 larger inequalities of surface. The north side of the hills are most-affected, 

 whilst from the southern side, long ridges, called oasars, stretch out ; they 

 are composed of sand and waterworn materials, and appear to be simi- 

 lar, but on a much larger scale, to the tails of diluvium in Scotland. In 

 Sweden, however, the erratic blocks always lie on the surface of these 

 ridges, and are not embedded within them : but M. Sefstrom says, that 

 at the time when the grooves were formed, enormous masses of rock were 

 torn from the mountains. In the United States, the phenomenon of the 

 grooved rocks appears to be developed in an extraordinary manner. Pro- 



* Mr. Lyell, moreover, describes (Philosoph. Transact., 1835, p. 18), 

 the rocks of gneiss on the beach near Oregrund in Sweden, as being so 

 " smooth and polished, that it is difficult to walk on them." Further on 

 (p. 21), he describes the large bodies of ice, which are annually packed 

 on this coast, so as to be eighteen feet thick : here then we have the 

 same phenomena as in the Alps ; and great icebergs in movement, instead 

 of solid glaciers. More lately M. Berzelius has sent specimens of these 

 rocks, " polisb.ed as if by emery in a constant rectilinear direction" ( Edinb. 

 New Phil. Journal, vol. 1., p. 313), to Paris, accompanied by a letter to 

 M. Elie de Beaumont. 



