312 



Proceedings of Societies. 



air are not the only causes of the increased radiation from a moving 

 body. (Compare Joule and Thomson, Phil. Trans. 1860.) A 

 vacuum apparatus now in course of construction, will, it is hoped, 

 lead to decisive results. 



Monday, Uh January 1864. — Professor KELLAND, V.P., 

 in the Chair. 



The following Communications were read 



1. On the great Drift-Beds wdth Shells in the South-west of 

 Arran. By the Eev. Eobert Boog Watson, B. A., F.E.S.E., 

 Hon. Mem. Naturw. Ver. Liineburg. 



These beds, as examined by the author, lie in the Torlin or Kil- 

 morie Burn basin, in the Scoradale or Slidry Water basin (more 

 strictly in the first north or north-west tributary of each, reckoning 

 upwards from the sea), and in the Clachan Grlen, — all in the south- 

 west of Arran. They are of great extent and depth ; at certain 

 points they contain boreal shells in considerable numbers. They 

 are divisible into two classes, (1.) underlying fine dark sands and 

 clays ; and, (2.) overlying coarse red clay with striated stones, pro- 

 bably boulder clay. 



They are interesting, because, 



1. They present, in a striking form, proof of the immense 

 destruction of the surface of the land. 



2. They afford unusually good sections, from the rock on which 

 they rest, upwards. 



3. They throw some light on the formation of the boulder clay. 



4. They present sea shells, at one point land plants, and also at 

 one point a later lake basin. 



The special information they give is, — 



1. That all the latest geological changes have not materially 

 affected the relations of hill and valley. 



2. That the valleys were largely excavated by ice. 



3. That the ice covered the land till it was submerged. 



4. That the depression of the land below the sea was con- 

 tinuous, and ultimately attained 1000 feet at least. 



5. That the depression was, at one point at least, sudden. 



6. That this sudden fall did not begin later, at least, than the 

 time at which the present 90 feet line above the sea -level reached 

 the level of the sea. 



7. That this sudden subsidence could not have amounted to less 

 than 200 feet. 



8. That it could not have much exceeded 800 feet. 



9. That under obvious limitations, the beds which lie nearest 

 the sea-level and deepest below the surface, are the oldest, and that 

 those are contemporary which occupy the same relative position to the 

 sea- level and the underlying rock. 



