NATURAL HISTORY SOCIETY OF GLASGOW. 113 



The oldest series of facts involved in the succession of changes to 

 be considered was connected with the Elephant Bed at Kilmaurs, 

 originally examined by Dr Scouler, and recently re-opened by 

 Dr Bryce, and those beds of sand, with little doubt coeval with it, 

 beneath the boulder clay at ChajDelhall, described by Mr Geikie. 

 Between this period when Elephas primogenius roamed over tliis 

 district, and came to drink at the large rivers, in the gravels of 

 which its bones are found at the present day, the land has been 

 depressed beneath the sea and again uplifted, while varied 

 climatic changes had taken place. At present, we have no 

 measure in Scotland of this great depression of land. In 

 Wales, an Arctic shell-bed has been found at Moel Tryfaen, at 

 the height of 1 360 feet above the sea, containing fifty-six species ; but 

 our highest known bed in Scotland is at Chapelhall, 510 feet. 

 The height of the boulder clay is generally taken for the measure- 

 ment of the depth of depression; but although some portions of 

 boulder clay have certainly been sunk beneath the sea, and placed 

 in a position in which they might possibly become the abode of a 

 spare fauna, yet its original formation must be attributed to 

 terrestrial rather than marine agencies; and it cannot be argued 

 that wherever there is boulder clay there is a clear proof of sub- 

 mergence beneath the sea. With regard to the fauna of the clay 

 beds, investigation intensifies the proof of its Arctic character. 

 In conjunction with Mr David Eobertson, he had been engaged in 

 microscopic examination of the clays, with very curious results. 

 Many species have been discovered — some new to science, and 

 some identical with new forms discovered by Dr Brady in mud 

 obtained from Baffin's Bay. Some species of a highly Arctic 

 character have also been added to the general lists, such as 

 Cyclostrema costulatum, which has never been found living south of 

 the Arctic circle, and Balanus carosus, a Spitzbergen species 

 described by Darwin. He added that he hoped to be able to 

 complete a full Ust of the fauna classified according to the various 

 beds, as we are now working upon this field. From the period of 

 extreme depression, the rise of land has been very gradual. The 

 proof of this is both physical and zoological. The physical con- 

 dition and position of the glacial shell beds invalidates the idea of 

 a violent upheaval. They rest in hollows of the old boulder clay, 

 and these hollows occur so rapidly within a limited area that any 



sudden upheaving force would have almost uniformly covered the 



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