314 Horner's Geological Address. 



of the Fiord, and they are there widest apart. It is evident, 

 therefore, that the movement of the land has been different 

 in different parts of the Fiord. It seems as if the continen- 

 tal mass had been elevated with an inclination seaward, the 

 axis of motion corresponding nearly to that of the great chain 

 of the mountains of Norway. It is most desirable, that mea- 

 surements similar to those of M. Bravais should be made in 

 all places where there are terraces or raised beaches, one 

 above another, along our coasts. Mr Darwin's explanation 

 of the parallel roads of Glen Roy, that they are ancient sea- 

 beaches, appears to be now generally accepted ; and it would 

 be most interesting, if it were ascertained by exact levellings, 

 such as those of M. Bravais in the Alten Fiord, whether they 

 are really parallel; because, as M. Bravais well remarks, 

 they may seem so to the eye, which can take in only a small 

 part of the space they occupy, while exact measurements 

 might prove that the appearances are deceptive. 



That land, in various parts of the earth, has undergone 

 movements of elevation and depression, and that it has been 

 subject to such oscillations at all times, up to the present day, 

 admits, I think, of no doubt. Without, therefore, going quite 

 so far as my friend Mr Darwin, who tells us, that " daily it is 

 forced home on the mind of the geologist, that nothing, not 

 even the wind that blows, is so unstable as the level of the 

 crust of this earth ;" still, I believe, it may be safely af- 

 firmed, that the stability of the sea, and the mobility of the 

 land, must be acknowledged to be demonstrated truths in 

 Geology. 



Boulder Formations and Erratic Blocks. 



The geologically modern changes in the relative level of 

 sea and land, are intimately connected with the history of the 

 vast accumulations over Northern Europe and North Ame- 

 rica of detrital matter, in the form of sand, clay, gravel, boul- 

 ders, and huge erratic blocks, and of the grooved, striated, 

 and polished surfaces of hard rocks, which usually accompany 

 them. This great problem, complicated in its nature, and 

 full of difficulties, has of late years more particularly arrested 

 the attention of geologists ; and it must long continue to do 



