3 I 6 RAMBLES OF A GEOLOGIST. 



Scotland generally, and of the Isle of Man, for they are all 

 palpably connected with the same iceberg phenomena, and 

 occur along the same zone in reference to the sea-level, were 

 formed during the existing geological epoch. 



These details may appear tediously minute ; but let the 

 reader mark how very much they involve. The occurrence 

 of recent shells largely diffused throughout the boulder-clays 

 of Caithness, at all heights and distances from the sea at which 

 the clay itself occurs, and not only connected with the ice- 

 berg phenomena by the closest juxtaposition, but also testify- 

 ing distinctly to its agency by the extremely comminuted 

 state in which we find them, tell us, not only according to 

 old John Busby, " that the ocean covered the inland country 

 at some former period of time," but that it covered it to a 

 great height at a time geologically recent, when our seas were 

 inhabited by exactly the same mollusca as inhabit them now, 

 and, so far as yet appears, by none others. I have not yet 

 detected the boulder-clay at more than from six to eight hun- 

 dred feet over the level of the sea ; but the travelled boulders 

 I have often found at more than a thousand feet over it ; and 

 Pr John Fleming, the correctness of whose observations few 

 men acquainted with the character of his researches or of his 

 mind will be disposed to challenge, has informed me that he 

 has detected the dressed and polished surfaces at least four 

 hundred feet higher. There occurs a greenstone boulder, of 

 from twelve to fourteen tons weight, says Mr M'Laren, in 

 his " Geology of Fife and the Lothians," on the south side of 

 Black Hill (one of the Pentland range), at about fourteen 

 hundred feet over the sea. Now fourteen or fifteen hundred 

 feet, taken as the extreme height of the dressings, though 

 they are said to occur greatly higher, would serve to sub- 

 merge in the iceberg ocean almost the whole agricultural re- 

 gion of Scotland. The common hazel (Gorylus avellana) 

 ceases to grow in the latitude of the Grampians at from 



