HO IV THE SOIL CAME. 43 



below are connected with it by a rounded channel. All of 

 these potholes were formed by water from the same 

 glacial stream, catching stones or pebbles and whirling 

 them so that they ground off particles for the water to 

 carry away. Many stones were worn out in the task, but 

 at least one of them remained in its place for about seven 

 thousand years for men to witness it. This was taken 

 out of the Pot by some one, and is now in the possession 

 of Charles S. Bates. It is a typical pothole bowlder 

 about four inches in diameter, of granite, worn very 

 smooth and round by much rolling. In other parts of the 

 town similar cavities have been dug. 



One of the most famous is the " Devil's Armchair," 

 only a foot across and nine inches deep. It is to be found 

 south of Beach Street on the highest part of the ledge, 

 two hundred feet back of Daniel Tower's home. A 

 smaller hole two feet below the chair is called the " Heel 

 Print," and a smooth channel connects them running, as 

 in the other cases, southeasterly. Government Island has 

 two more of these hollows, very shallow, side by side on 

 the southeasterly shelf of its rock, called "Adam's and 

 Eve's Seats " ; while another cavity, called a " Footprint," 

 is just behind, about one rod to the west. 



How many more of these interesting formations are 

 covered by the soil it is hard to estimate. There is one 

 more important one, near the Black Rock House, on a 

 bare surface of granite sloping down to the sea, only two 

 or three feet above high tide. It is a pear-shaped basin, 

 thirty-three inches by forty-one inches in diameter and 

 eighteen inches deep at one end. 



After the formation of these potholes the great ice 

 sheet must have drawn its long labors to a close. Its 

 movement ceased, and all the bowlders which had been 

 pushed along from the direction of Hingham and Hull 

 stopped their pilgrimage to rest upon the ledges where 

 they now are. The most famous of these is Tipling Rock, 



