ii.] THE PEBBLES IN THE STKEET. 57 



ance of the dried sea-bottom would be a dreary and 

 lifeless waste of sands, gravels, loose boulders, and 

 boulder-bearing clays ; and wherever a boss of bare 

 rock still stood up, it would be found ground down, 

 and probably polished and scored by the ponderous 

 icebergs which had lumbered over it in their passage 

 out to sea. 



In a word, it would look exactly as vast tracts of 

 the English, Scotch, and Irish lowlands must have 

 looked before returning vegetation coated their dreary 

 sands and clays with a layer of brown vegetable soil. 



Thus, and I believe thus only, can we explain the 

 facts connected with these boulder pebbles. No 

 agent known on earth can have stuck them in the 

 clay, save ice, which is known to do so still elsewhere. 



No known agent can have scratched them as they 

 are scratched, save ice, which is known to do so still 

 elsewhere. 



No known agent certainly not, in my opinion, 

 the existing rivers can have accumulated the vast 

 beds of boulders which lie along the course of certain 

 northern rivers ; notably along the Dee about Aboyne 

 save ice bearing them slowly down from the distant 

 summits of the Grampians. 



No known agent, save ice, can have produced those 

 rounded, and polished, and scored, and fluted rockers 

 moutonnes " sheep-backed rocks" so common in the 

 Lake district; so common, too, in Snowdon, especially 

 between the two lakes of Llanberis; common in Kerry; 

 to be seen anywhere, as far as I have ascertained, 

 around the Scotch Highlands, where the turf is 

 cleared away from an unweathered surface of the 



