IL] THE PEBBLES IN THE STREET. 49 



shore, near Edinburgh ; or, to give one more instance 

 out of hundreds, along the coast at Scarborough. If 

 you walk along the shore southward of that town, you 

 will see, in the gullies of the cliff, great beds of sticky 

 clay, stuffed full of bits of every rock between the 

 Lake mountains and Scarborough, from rounded 

 pebbles of most ancient rock down to great angular 

 fragments of ironstone and coal. There, as elsewhere, 

 the great majority of the pebbles have nothing to do 

 with the rock on which the clay happens to lie, but 

 have come, some of them, from places many miles 

 away. 



Now if we find spread over a low land pebbles 

 composed of rocks which are only found in certain 

 high lands, is it not an act of common sense to say 

 These pebbles have come from the highlands ? And 

 if the pebbles are rounded, while the rocks like them 

 in the highlands always break off in angular shapes, is 

 it not, again, an act of mere common sense to say 

 These pebbles were once angular, and have been 

 rubbed round, either in getting hither or before they 

 started hither ? 



Does all this seem to you mere truism, my dear 

 reader ? If so, I am sincerely glad to hear it. It was 

 not so very long ago that such arguments would have 

 been considered, not only no truisms, but not even 

 common sense. 



But to return, let us take, as an example, a sample 

 of these boulder clay pebbles from the neighbourhood 

 of Liverpool and Birkenhead, made by Mr. De Ranee, 

 the government geological surveyor : 



Granite, greenstone, felspar porphyry, felstone, 

 quartz rock (all igneous rocks, that is, either formed 



SC. E 



