160 GLACIAL GRAVELS OF MAINE. 



PALERMO-WARREN SYSTEM. 



This system begins iu Palermo near where the towns of Palermo, 

 Freedom, and Montville join. Here a north-and-south ridge of till becomes 

 more stony toward the south, and by degrees passes into unmistakable gla- 

 cial gravel within one-fourth of a mile. The fact that the glacial gravel 

 consists of the till with the finer detritus washed out of it is here well 

 exhibited. Near the east branch of the Sheepscot River this ridge turns 

 southwestward, and follows the valley for several miles. This stream flows 

 along the northern base of the high northeast-and-southwest range of which 

 Hogback Mountain in Montville is a part. Much of the way along the 

 valley the gravel is in the form of a ridge, but it becomes terrace-like and 

 somewhat discontinuous as it approaches Sheepscot Grreat Pond. This 

 pond lies in the midst of a cirque 5 miles in diameter. This broad, rather, 

 level valley is surrounded on all sides by rather high hills except at a few 

 narrow passes. The lowest depression is southwest down the valley of the 

 east branch of the Sheepscot River, but the glacial waters rejected the valley 

 of natural drainage and took a course over higher ground to the south and 

 southeast. Two lines of glacial gravel extend from Sheepscot Grreat Pond 

 southward. For 2 or 3 miles they are nearly parallel and only from one- 

 fourth to one-half mile apart. The western series takes the form of an osar- 

 plain one-eighth to one-fourth mile wide. It penetrates a low pass along 

 the western base of the high granite peak called Patrick Mountain, and 

 continues as an osar-plain till it nears Jones Corner, on the road from 

 Somerville to South Liberty. Here it takes the form of a two-sided ridge 

 of arched cross section for about 1 mile. In this part of its course it turns 

 east by a rather abrupt curve and then closely skirts the soutliern base of 

 Patrick Mountain. In so doing it crosses a hill about 76 feet high, the 

 gravel disappeai-ing for one-third of a mile on the up slope. Near the top 

 of this hill it takes the form of an osar-plain for a short half mile, and then, 

 on a steep down slope, there is no gravel for near 1 mile to Branch Stream, 

 which flows south into Damariscotta Great Pond at East Jefferson. 



We now go back to the swampy plain south of Sheepscot Great Pond 

 in the midst of the remarkable Palermo basin, where the two lines of glacial 

 gravel are found side by side. The more eastern of the two formations has 

 the form of a broad osar, with arched cross section. It soon diverges from 



