352 GLACIAL GEAVELS OF MAINE. 



Big Creek. Numerous lateral vallej^s extend from the main creek from 5 

 to 10 miles into the mountains. The area of this ^Dart of the valley is 

 about 300 square miles. The elevation of' the Falls of Napius (or Bull of 

 the Woods) is about 5,700 feet. Lying east of this point is an area of 

 several square miles of volcanic rock, then a crescent of schists and quartz- 

 ites, and around that a crooked belt of granites. This makes it easy to dis- 

 tinguish local from transported matter. 



The lateral valleys and cirques were once filled by glaciers which 

 united in the main valley to form a large glacier or ice-sheet that rose 

 above the hills adjoining the main creek so as to extend back for a mile or 

 more into the lateral valleys. This is proved by the following facts: 



The quartzites resist chemical decay, but readily fracture. The 

 volcanic rocks, granites, and schists yield to both fracture and chemical 

 action. Hence the exposed rock has seldom preserved its glacial scratches. 

 Fresh exposures reveal glaciated rock in various places in the valley. 



MORAINES. 



Moraines of four kinds were observed. 



Lateral moraines. — The slopBs of the luUs ncxt to the Hiaiu valleys are 

 strewn with a scattering of erratic material, but no distinct or prominent 

 ridges or terraces were found. 



Terminal moraines. — About 2 uiilcs cast of tlic Falls of Napius is a moraine 

 on the north side of the creek beginning near the stream and extending at 

 nearly a right angle to the creek northward up to an elevation of about 800 

 feet above the creek. It forms a series of low ridges with some outlying 

 spurs. The mountainside on which it lies rises pretty steeply from the 

 stream. The great depth of the ice at this point makes it certain that the 

 glacier extended far beyond the region explored; hence this is a retreatal 

 moraine. The moraine corresponding to this on the south side of the creek 

 has disappeared near the stream on a very steep slope. There are several 

 other small terminal or retreatal moraines above this at intervals in the 

 valley. 



Crag and tail. — The high grauitc ridge which extends northeastward from 

 the Falls of Napius shows no erratics till we reach a point three-fourths of a 

 mile north from the creek. Here on a broader part of the ridge is a moraine 

 ■consisting of well-glaciated stones with a few bowlders. It forms a sheet 



