ANNIVERSARY ADDRESS OF THE PRESIDENT. 199 



deal more*". It is possible that these may be mere inaccuracies of 

 expression in describing changes of relative level of sea and land, 

 but if they are so they ought to be guarded against, for they may 

 be very easily misapprehended ; and they tend to perpetuate an error 

 that leads to the most false reasoning on many changes on the earth's 

 surface. 



If the land of Norway had been immovable, if the sea had fallen 

 from a higher level, the lines of its former shores, as it sank at in- 

 tervals, would have been continuous and parallel ; but the raised 

 beaches are, within short distances, at different elevations ; other 

 observers had remarked this, but it is to M. Bravais that we are in- 

 debted for the first exact measurements of the relative positions of 

 the successive terraces, and these have demonstrated that their par- 

 allelism is only apparent. During his residence on the Alten Fiord, 

 near North Cape, he extended his levelings over a space of from 

 nine to ten myriametres, that is, from about fifty-five to sixty-two 

 English miles ; and he ascertained that the two great lines of ancient 

 level there, which are on a slope rising from the sea, come nearer 

 and nearer to each other as they approach the present shore ; their 

 greatest elevation is in the upper part 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 continental mass had been elevated with an inclination sea- 

 ward, 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 levelings, 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. Dar- 

 win, 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 

 affirmed, that the stability of the sea and the mobility of the land 

 must be acknowledged to be demonstrated truths in Geology. 



Boulder Forinatio7is and Erratic Blocks. 



The geologically modern changes in the relative level of sea anil 

 land are intimately connected with the history of the vast accuum- 



* Edin. Phil. Journal, January 1846. 



