130 
GLACIAL PHENOMENA IN MAINE. 
excavations made by the quarrying operations 
in these rocks give the most admirable chan¬ 
ces for investigation. These slates are them¬ 
selves of admirable quality, and are much used 
as roofing-slates. About a mile to the west of 
the quarries, near Merrill, there are large mo¬ 
rainic accumulations of loose materials of the 
kind I have called bottom or ground moraines, 
though here they are not exactly in the form 
of horsebacks. Immediately above the quar¬ 
ries at Brownville, where the drift has been 
recently removed to facilitate the quarrying, 
there are good sections where these bottom 
moraines, trending in the direction of the hills 
to the east of the valley, may be easily studied. 
They rest immediately upon the edges of the 
upturned beds, the whole mass being a mix¬ 
ture of the most heterogeneous rocky materi¬ 
als uniformly mixed. Nowhere in this neigh¬ 
borhood have I seen anything like a distinct 
lateral moraine; but near the church, an un¬ 
mistakable terminal moraine, across which the 
river has cut its bed, spans the valley. The 
exhibition of glacial phenomena is so complete 
here, that it seems superfluous to follow simi¬ 
lar facts through localities where, owing to the 
