THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OP SCIENCE. 



— + — 



[FOURTH SERIES.] 



MA Y 1864. 



LIII. On the Physical Cause of the Glacial Epoch. By~E. Erank- 

 land, F.R.S., Professor of Chemistry in the Royal Institution*. 



AMONGST the causes that have profoundly influenced the 

 present physical condition of our earth, the action of 

 ancient glaciers upon a scale of almost inconceivable magnitude 

 has gradually but irresistibly forced itself upon the notice of 

 philosophers, since their attention was first called to it by Venetzf 

 in Switzerland, and Professor EsmarkJ in Norway. There are 

 few elevated regions in any quarter of the globe which do not 

 exhibit indubitable evidence of the characteristic grinding and 

 polishing action of ice-masses, although at present perhaps they 

 are scarcely streaked by the winter's snow. The researches of 

 Dr. Buckland and others first revealed the evidence of this 

 ancient glacial action in Great Britain ; but it is especially to 

 Professor Ramsay that we are indebted for our present extensive 

 knowledge of the effects produced in this country during the 

 glacial epoch. His explorations have demonstrated that the 

 Highlands of Scotland, and the mountains of Wales and Cumber- 

 land, to which I would add the limestone crags of Yorkshire, 

 abound in these roches moutonnees, which leave no doubt that the 

 valleys of these mountain-ranges were once filled with glaciers of 

 dimensions unsurpassed, if even equalled, by those which at the 

 present day stream down the sides of their gigantic Swiss rivals. 

 Not only was there this development of perennial ice where no 

 such phenomenon is now observed, but the glaciers of the pre- 



* Communicated by the Author. 



t Transactions of the Swiss Natural History Society, vol. i. part 2 (1821). 



% Edinburgh New Phil. Journ. vol. iii. (1827). 



Phil Mag. S. 4. Vol. 27. No. 183. May 1864. Y 



