On the Traces of a Vast Ancient Flood. 71 



maining ; it has formed the furrows by the dragging along of 

 stones over the ridges, and on the east and west declivities of 

 mountains. During its rapid transit, it has thrown these stones 

 in a sort of arch -behind the south sides, which latter, therefore, 

 it could not so abrade and furrow ; indeed, the south sides have 

 thus preserved their sharp edges and angles, and no furrows 

 are to be discovered on them provided the declivities are not 

 very sHghtly inclined. Behind such a southern declivity we 

 can perceive the spot where the boulders have been precipitat- 

 ed from the upper portion, and this is recognised by its deeper 

 abrasion. The deviation in the direction of the furrows on the 

 side of the mountain, is always such as must have resulted from 

 the direction of the flood being diverted by the resistance of the 

 mountain, on the east side towards the left, and on the west 

 side towards the right. By a comparison of the direction of 

 the furrows in different places we therefore find that the lofty 

 ridges, the greater, higher, and broader they are, have in pro- 

 portion diverted the flood round their declivities ; but upon 

 the top the flood has always preserved its original direction. — 

 This flood has always shattered in pieces, and transported to 

 great distances, a number of loose fragments of the older and 

 younger formations. Thus we know that large portions have 

 been torn away from t e transition formation of West Goth- 

 land, and that of these, distinct traces are still met with on the 

 masses of trap which have been erupted from this formation, 

 and have withstood the violence of the flood. Even on these 

 trap rocks Sefstrom has seen the furrows produced by the stones 

 that have been rubbed along their surfaces. 



So far as we can conclude from the observations hitherto 

 made, the masses carried along by the flood must have attain- 

 ed a height of at least 1500 feet, but on mountains higher 

 than 1500 feet there are no traces of furrows. The period of 

 this flood, according to geological reckoning, must evidently 

 have been coeval with that of the Diluvium, or possibly some- 

 what more recent. But it was anterior to the dispersion of 

 the boulders, that is of the loose blocks of rock which lie scat- 

 tered in such abundance on the surface of the earth ; for these 

 blocks when they occur with asar always lie on them and fre- 

 quently near their crests. 



