HOW THE SOIL CAME. 49 



ledges, and there the ice movement must have been very 

 much slower than upon the top, just as a stream of water 

 tumbles along the pebbles on the bottom sometimes not 

 one hundredth part as fast as the bubbles are scudding 

 upon its top. 



The bigger the bowlder the shorter its travels, is a fair 

 rule for a guesser of the origin of our bowlders. Along 

 our shore upon the beach there have been found some little 

 pebbles of red felsite which came undoubtedly across Bos- 

 ton Harbor from their ledge in Saugus, eighteen miles 

 away. A darker kind of red felsite has been rubbed 

 off from a ledge in Hingham near Bradley's Hill, and 

 scores of the pieces have been lodged in Beechwood, 

 five miles away, where they have been used in building 

 stone walls by settlers who never suspected the origin of 

 them.* 



The same kind of filching from the ledges of Hull, 

 northwest of Straits Pond, and from Planter's Hill and 

 other parts of Hingham has supplied us with pudding 

 stones scattered at intervals over the town. No ledge of 

 pudding stone exists in the town, save a small outcrop just 

 at the edge of Straits Pond. 



Speckled pieces of porphyrite and fragments of slate 

 from out of town were brought to us ; but nearly all of our 

 large bowlders are homemade from granite ledges within 

 a few miles or less of their present abodes. 



At about the same time when the bowlders came to a 

 standstill beneath the ice, the ice itself grew weary of 

 crawling. It lay deep and thick in every low place, while 

 every high ledge over which it bent made cracks through 

 it and hastened the sun's work at that point. 



For many dozens of years, perhaps hundreds, the 

 separated fragments of the dying glacier lay melting 

 between the ledges. They were covered with dirt which 



*Dr. Oliver H. Howe has noticed fourteen of these red felsite stones in the 

 walls by the roads. He has carefully marked their positions upon a map. 



