GLACIAL POTHOLES. 327 



shore situated a foot or two above high tide. It is 2 feet in diameter and 

 4 feet deep. About 4 feet west of this hole is a shallow bowl with very 

 smooth inner surface, an incipient pothole. There are several masses of 

 water-rounded gravel near here, which at the time of my visit I supposed 

 to be esker gravel, probably deposited by the same glacial stream that 

 formed the potholes. I am now uncertain whether it is ■ esker or beach 

 gravel. 



No one familiar with potholes could fail to recognize as potholes these 

 round wells with smoothly polished inner surface, even if he did not find 

 within some of them the round cobbles and smoothed bowlders used in 

 grinding out the cavity. All are found on short slopes. There is hardly a 

 grass field in Maine that would not contain jDOtholes if these were produced 

 by land waters. The potholes are manifestly in places where no ordinary 

 streams can ever have flowed, and must be due to the action of glacial 

 streams. These potholes are found in a region where there is a larger 

 proportion of bare rock than in any other part of the Maine coast. They 

 are situated a few miles east of the Kennebec River. At the time the sea 

 stood at the 225-230-foot level the whole region was deeply under water 

 and exposed to the force of the Atlantic. The rocks are gneissoid and 

 schistose, which rocks usually produced more till than is seen in this region. 

 The scarcity of till is in part due to marine erosion and in part to the sub- 

 glacial streams. If other regions were as bare of till as this, it is possible 

 we might find glacial potholes everywhere along the coast. It is incredi- 

 ble that Indians excavated holes such as these. 



In the interior of the State the only potholes known to me are found 

 in the beds of streams, with a single exception. This is situated in the 

 town of Paris, about one-half mile west of Snows Falls. It was first 

 pointed out to me by Mr. N. H. Perry, mineralogist, of South Paris. By 

 aneroid it is 240 feet above Snows Falls. Above these falls the valley of 

 the Little Androscoggin widens into a triangular basin 3 miles in diameter. 

 The pothole is situated near the top of a hill lying directly south of this 

 broad open valley, and if the valley were filled by a glacier the ice would 

 naturally abut against this hill. From the highest point of the hill (about 

 300 feet above the river) a ridge extends northeastward down the slope. 

 At one place this ridge is cut across at right angles by a ravine 100 feet 

 wide, bordered on each side by steep rocks rising about 20 feet. On the 



