276 PROCEEDINGS OE T'HE GEOLOGICAL SOCIETY. [Feb. 7, 



The glacial beds of the south of Arran (first described by the Eev. 

 II. B. Watson, and more recently explored by Dr. Bryce and the Eev. 

 H. W. Crosskey) seem to have many points of resemblance to those 

 of King-Edward. There are beds of fine clay containing Arctic 

 shells, sometimes in a broken or crushed state, but occasionally en-' 

 tire and apparently i7i situ. This fossiliferous stratum is covered 

 by a great thickness of what Mr. Watson calls " Boulder-day/' but 

 which Messrs. Bryce and Crosskey term " Upper Drift hedsJ^ If I 

 understand Mr. Watson rightly, this upper stuff occasionally contains 

 broken shells. The fine fossiliferous clay sometimes rests immedia- 

 tely on the older rocks, at other times, according to Messrs. Bryce 

 and Crosskey, there is a mass of clay beneath it of harder, coarser 

 texture than what lies above, and containing stones and boulders on 

 which glacial action is more apparent, and they would restrict the 

 term " boulder-clay^' solely to this lower stufi". Mr. Watson mentions 

 the occurrence of glacial beds beneath the fine shelly clay, but, ac- 

 cording to him, they vary a good deal in character, and he does not 

 draw the same strict distinction between them and the upper beds. 



If want of stratification, hardness of texture, and abundance of 

 well-glaciated stones and boulders are to be the tests for what we 

 should call genuine Boulder-clay, then much of the Caithness Drift 

 will stand the ordeal, and, moreover, the shells are as well glaciated 

 as the boulders. The upper pebbly mud of King-Edward is also 

 often very hard and firm. 



If the Old Boulder-clay or till has been produced, not in the sea 

 but by glacier-ice moving on the land, it ought to be devoid of 

 marine fossils. What we now want is a microscopic examination of 

 our various so-called Boulder-clays. Messrs. Anderson and Peach 

 have made a commencement with those of Caithness, and find them 

 full of minute organisms. This was to be expected from the presence 

 of the sea-shells. The Boulder-clay, however, which lies beneath 

 the beds of Arctic shells in the midland region of Scotland is remark- 

 able for the absence of fossils, but it yet remains to be seen how it 

 will stand the test of washing and microscopic examination. 



9. The post- Glacial period in Caithness. — So far as I observed, the 

 post-glacial conditions in Caithness do not appear to have differed 

 much from those in the rest of Scotland. Some indications of a 

 submerged forest, or old land- surface, occur at Sinclair Bay. The 

 peat bed, close upon the shore at Aekergill, contains clusters of seeds 

 of land-plants and also some remains of trees or bushes. Mr. 

 Cleghorn, of Wick, thinks this peat bed is a marine deposit of matter 

 carried into the sea by the rivers. After examining it in company 

 with him I am inclined to differ from this opinion. The peat is 

 covered by a mass of blown sand, Avhich has insinuated itself into 

 some of the crevices and openings of the peat, but I saw nothing to 

 induce me to believe that there was any interstratification. of peaty 

 matter with marine sediment. 



Mr. Dick told me that at Thurso some peat, containing hazel-nuts 

 and twigs, had been got near the beach on the west side of the 

 town, but I could not learn whether it was in situ or transported. 



