GLACIAL PHENOMENA IN MAINE. 127 
and when the lower tracks were inundated 
by the melting of the general sheet of ice, the 
water, as it rose, may have floated off the re¬ 
maining bergs, and drifted them across the 
normal primary scratches bearing due north. 
On our return from the Katahdin Iron 
Works our road lay through Brownville, Orne- 
ville, Bradford, Hudson, and then along the 
shore of Pusliaw Lake, to Bangor. Through¬ 
out this whole tract scratched and polished 
surfaces and roches moutonnees are frequent. 
But the most instructive localities of all, in 
reference to glacial phenomena, are to be 
found near the slate quarries of Brownville. 
Here again, as in the roches moutonnees at 
Pusliaw Lake, the marks run at right angles 
with the trend and dip of the beds. To ex¬ 
plain fully the significance of the facts in this 
region, I must say something of its general 
formation. Pleasant Biver runs through a 
wide, open valley, the direction of which is 
very nearly from north to south. The finely 
laminated clay beds in which the slate quarries 
are excavated are lifted to an angle of seventy 
degrees and more, that is, standing almost 
vertically; and their trend is across the valley 
