NATURAL HISTORY SOCIETY OF GLASGOW. 253 



organisms found in tlie mud bed. He further stated that the 

 antiquity of these organisms, and of the sand and mud beds of the 

 Crofthead section, depended entirely upon the correct identification 

 of a so-called bed of boulder till which Avas stated to have over- 

 lain the mud bed at one point of the section. If this could be 

 shown to have been produced by a land slip of the older boulder 

 till from the hill side over part of the old lake bottom, then the 

 underlying beds, with their organisms, might l)e of comparatively 

 modern date. Mr Young stated that he had not seen the disputed 

 beds, but that he was very sceptical as to the upper bed of boulder 

 till having been laid down by a second sheet of glacier ice passing 

 along the valley. The thickness of the mud, sand, and gravel 

 beds showed that a long period of time must have elapsed during 

 their formation, and he therefore thought that the whole of the 

 phenomena might yet be explained without bringing in such a great 

 physical revolution as a second ice period. Mr Young also stated 

 some of his objections to the boulder till of the low lying districts 

 of Scotland being viewed as a formation resulting from the melting 

 of a great sheet of land ice lying above sea level, when there is 

 every reason to believe that not only those districts where the 

 boulder till lies thickest, but the whole country was depressed 

 many hundred feet below the present sea level during the great 

 ice period. 



The Eev. H. W. Crosskey explained the great difficulties con- 

 nected vntli the section, and asked for judgment to be reserved 

 until some fresh cuttings had been exposed. Mr Eobertson and 

 himself had found in the clay several species of fresh-water 

 Entomostraca which were common in the Paisley Canal at the 

 present day. The boulder clay hangs in patches along the sides 

 of the valley, and has evidently been subjected to great denudation. 

 A mass hanging by the side of the old lake might have been 

 undermined and brought down gradually by the water. On the 

 north east, before approaching the boss of trap, a peaty bed, with 

 nuts and branches of various trees, occurs, evidently of compara- 

 tively modern origin. The question is whether the bed in 

 which Bos immegenius was found does not correspond with 

 thisr- There is great difficulty in conceiving how the passage of a 

 second glacier could have left the clays and sands and gravels 

 preserved in their present condition and position. The whole 



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