COMMENCEMENT OF PRESENT SPECIES. 73 



Our attention is next drawn to the erratic blocks or 

 Douldeis, which in many parts of the earthy are thickly 

 strewn over the surface, particularly in the north of Eu- 

 rope. Some of these blocks are many tons in weight, yet 

 are clearly ascertained to have belonged originally to situ- 

 ations at a great distance. Fragments, for example, of the 

 granite of Shap Fell are found in every direction around, 

 to the distance of fifty miles, one piece being placed high 

 upon Criffel Mountain, on the opposite side of the Solway 

 estuary ; so also are fragments of the Alps found far up 

 the slopes of the Jura. There are even blocks on the east 

 coast of England, supposed to have travelled from Nor- 

 way. The only rational conjecture which can be formed 

 as to the transport of such massses from so great a dis- 

 tance, is one which presumes them to have been carried and 

 dropped by icebergs, while the space between "their ori- 

 ginal and final sites was under ocean. Icebergs do even 

 now carry off such masses from the polar coasts, which, 

 falling when the retaining ice melts, must take up situa- 

 tions at the bottom of the sea, analogous to those in which 

 we find the erratic blocks of the present day. 



As the diluvium and erratic blocks clearly suppose one 

 last long submersion of the surface, (last, geologically 

 speaking,) there is another set of appearances which as 

 manifestly show the steps by which the land was made 

 afterwards to reappear. These consist of terraces, which 

 have been detected near, and at some distance inland from 

 the coast of Scandinavia, Britain, America, and other re- 

 gions ; being evidently ancient beaches, or platforms, on 

 which the margin of the sea at one time rested. They 

 have been observed at different heights above the present 

 sea-level, from twenty to above twelve hundred feet ; and 

 in many places they are seen rising above each other in 

 succession, to the number of three, four, and even more. 

 The smooth flatness of these terraces, with generally a 

 slight inclination towards the sea, the sandy composition 

 of many of them, and, in some instances, the preservation 

 of marine shells in the ground, identify them perfectly 

 with existing sea-beaches, notwithstanding the cuts and 

 scoop ings which have every here and there been effected 

 in them by water-courses. The irresistible inference from 

 the phenomena is, that the highest was first the coast-line ; 

 then an elevation took place, and the second highest be- 

 came so, the first being now raised into the air and thrown 



