56 TOWN GEOLOGY. [n. 



But let us go a step farther; and, bearing in our 

 minds what live glaciers are like, let us imagine what 

 a dead glacier would be like ; a glacier, that is, which 

 had melted, and left nothing but its skeleton of stones 

 and dirt. 



We should find the faces of the rock scored and 

 polished, generally in lines pointing down the valleys, 

 or at least outward from the centre of the highlands, 

 and polished and scored most in their upland or 

 weather sides. We should find blocks of rock left 

 behind, and perched about on other rocks of a different 

 kind. We should find in the valleys the old moraines 

 left as vast deposits of boulder and shingle, which 

 would be in time sawn through and sorted over by the 

 rivers. And if the sea-bottom outside were upheaved, 

 and became dry land, we should find on it the remains 

 of the mud from under the glacier, stuck full of stones 

 and boulders iceberg-dropped. This mud would be 

 often very irregularly bedded ; for it would have been 

 disturbed by the ploughing of the icebergs, and 

 mixed here and there with dirt which had fallen from 

 them. Moreover, as the sea became shallower and 

 the mud-beds got awash one after the other, they 

 would be torn about, re-sifted, and re-shaped by 

 currents and by tides, and mixed with shore-sand 

 ground out of shingle-beach, thus making confusion 

 worse confounded. A few shells, of an Arctic or 

 northern type, would be found in it here and there. 

 Some would have lived near those later beaches, some 

 in deeper water in the ancient ooze, wherever the ice- 

 berg had left it in peace long enough for sea-animals 

 to colonise and breed in it. But the general appear- 



