66 History of Hingham. 



approximating to the termination of the great ice-sheet. Some 

 of our ridges, notably those of Great Hill, have an east-west 

 direction, such as it is supposed the glacier itself had near its 

 closing period over eastern Massachusetts ; but others or portions 

 of others vary so as to be found running in every direction. 



BOWLDERS. 



Bowlders are found scattered over all parts of the North within 

 the region occupied by the ice, having been borne by it from more 

 northern positions than those they now occupy. With a knowl- 

 edge of the direction of the movement of the glacier, they can 

 often be traced to the locality whence they came. 



A marked instance, often cited by geologists, and previously 

 mentioned in the preliminary remarks upon the glacial period, is 

 that of bowlders found south of Providence, of a character readily 

 recognized, being those of a porphyritie iron ore from a well- 

 known bed at Cumberland, R. I. They exist in the soil or upon 

 the surface for a distance of thirty-five miles or more in the direc- 

 tion mentioned, but are never found in any other. So of all 

 bowlders found. If of distinctive character, they are often recog- 

 nized as belonging to rock formations north, sometimes more 

 tban a hundred miles distant. 



They vary much in size, from cobble-stones to masses of enor- 

 mous magnitude, such as it is hard to realize have been trans- 

 ported great distances. There are none in Hingham equal in 

 dimensions to those found elsewhere. One of the largest ob- 

 served by the writer is in woods bordering Rockland Street, but 

 a few feet from the road upon the right side going east, not far 

 from the foot of Old Colony Hill. It is of granite and measures 

 nineteen feet in length, sixteen in width, and seventeen in height 

 = 5,168 cubic feet. The weight of this must be over 430 tons. 

 Some large masses have become detached from the main body 

 and these are included in the estimate of size and weight. Large 

 as this bowlder is, it is small compared with one in the town of 

 Madison, N. II., which measures 75 X 40 X 30 feet = 90,000 

 cubic feet, and which consequently weighs over 7,500 tons. 



Great numbers of bowlders are found together in certain locali- 

 ties of this town, the most notable of which is that of the south- 

 western slope of Prospect Hill, where they cover a large portion 

 of the surface. 



On the northeast slope of Otis Hill are a few bowlders which 

 call for particular notice from the fact that they are of granite 

 and that no rock of this kind occurs north of the hill less than 

 fifteen miles distant. The ice therefore must have transported 

 them at least as far as that and possibly very much farther. 



There is a bowlder now to be seen in what was once an exten- 

 sive kame hill known as Cobb's Bank, which is fast disappearing 

 by being dug away. The bowlder projects from the face of the cliff 



