34 SURFACE GEOLOGY. 



logical reasoning, will d»ubt that some other agent must be called in to explain 

 their formation ; and their position and relative elevation, as stated above, are 

 important elements in forming a theory of their origin. But more on this subject 

 in the sequel. 



2. Surface Geology in Europe. 



It is not my intention to give even a summary of the facts collected by Mr. 

 Chambers and others upon surface geology in Europe, except perhaps to refer to a 

 few of them; but, having travelled through several European countries since my 

 attention was turned to this subject, I could not but have my eyes open to it as I 

 passed over the surface. The results of my hasty observations I will now give, 

 though aware that they may be comparatively of little importance. 



Wales. 



It happened that the first country which I visited after landing at Liverpool, was 

 North Wales, and not expecting to go there when I left home, I had not refreshed 

 my memory with the statements of English geologists respecting its surface geology, 

 and, therefore, I passed over its lofty mountains and through its rugged passes, with 

 no hypothesis in mind, or expectation of what I should meet. In going from Car- 

 narvon to Llanberris, I thought the detritus, to the height perhaps of 300 feet above 

 the sea, indicated sea action ; that is, the detritus was not coarse drift, but had been 

 worked over by the action of water. Above that height I found occasionally small 

 accumulations of rounded and comminuted materials, in some partially sheltered 

 spots on the sides of the steep mountains. The highest spot of this kind on Snowdon, 

 my barometer made 2547 feet above the ocean; but in the higher, or rather midway 

 heights of Snowdonia, my attention was arrested by the marks of ancient glaciers. 

 I had not then seen a glacier, but the marks were so obvious that I could not hesi- 

 tate to refer them to that agency, and the conviction is still stronger since I have 

 been among the Alps of Switzerland, and especially since I have learnt the opinion 

 of Professor Kamsey, who has charge of the geological survey of Great Britain. 

 He finds drift in those mountains 2300 feet high, and thinks that there have been 

 two periods of glaciers there, one before and the other since the drift period. But 

 I will give more details on this point in my paper on the Ancient Glaciers of Hoo- 

 sac and Green Mountains. 



I ought to add, that I saw scarcely any terraces in Wales, nor were the ancient 

 beaches at all striking. On Cader Idris I saw none; but east of that mountain, 

 on the road to Machynleth, is a pass, 762 feet above the ocean by my barometer, 

 and there I saw some evidence of a beach. Although there is proof enough that 

 Wales has been again and again, and for vast periods beneath the ocean, and expe- 

 rienced deep denudation, I did not see there as much evidence of its last drainage 

 as in Scotland or New England, 



