Glacial Action on the Bocks about Edinburgh. 301 



Upon the Identity of the Marks of Glacial Action on the Rocks 

 in the Environs of Edinburgh^ with those observed by the 

 Author on the Continent of Europe and in Spitzbergen. 

 By CiiAiiLES Martins, M.D., Secretary of the Geological 

 Society of France, &c., &c. Communicated by the Author. 



I have no intention of describing in detail the traces 

 which these glaciers have left behind them in the neighbour- 

 hood of Edinburgh, this task having been already accom- 

 plished in the most satisfactory manner by Sir' James Hall, 

 Professors Agassiz and Buckland, Mr Charles Maclaren, 

 and Mr Robert Chambers. These traces are, 1^^, Those of 

 mountain-rocks, polished and striated, and identical with 

 those which are seen beneath and upon the flanks of existing 

 glaciers, and in all the Swiss valleys, which have been the 

 seats of ancient glaciers ; 2d, A clay called till or boulder-clay, 

 more or less pure, filled with boulders, angular or irregularly 

 rounded, striated in all directions, resembling those which 

 are so universally found under existing glaciers ; 3^?, Angular 

 blocks derived from the northern mountains. Compared 

 with the basin of Switzerland or with the plain of the Po, 

 the lowlands of Scotland are destitute of true moraines, and 

 of that thick aqueous diluvium upon which they repose. But 

 for these differences the analogy with the Vosges, Switzer- 

 land, and the Pyrenees is complete ; it is still more so if we 

 compare the phenomena of the erratics of Scotland with 

 those of Scandinavia. At the same time, I may remark, 

 that I have not observed, in those parts of the country I 

 have visited, those hillocks of sand covered with erratics 

 which are analogous to the Osars of Sweden. 



At the last meeting of the British Association held in 

 Edinburgh in August 1850, the Geological Section, upon 

 the suggestion of its president, Sir Roderick Murchison, 

 devoted an entire sitting to the discussion of the causes 

 of these interesting phenomena. Two systems were brought 

 under review ; the former ascribing the above phenomena to 

 the action of floating icebergs, which, influenced by power- 



