Glaciaiion of Mountains^ Etc. — Upham. 171 
ton and adjacent peaks of the same range, and with the moun- 
tains of gneiss in northern Labrador, near cape Chudleigh, 
which latter in their lower part are rounded and moulded by 
ice, but above present more angular and irregular outlines, 
and are profusely covered with loose l)locks detached by frost.* 
The elevation of the liighest part of th(( coast range of Labra- 
dor, seventy miles south of cape Chudleigh, is estimated by 
Dr. Robert Bell to be about 6,(X)0 feet above tlie sea ; and he 
states that throughout the drift period its top "stood above 
the ice and was not glaciated." ^ 
Photographs of the upper portion of Katahdin, kindly sent 
me by Mr. George H. Witherle, of Castinc, Elaine, show well 
its wonderful profusion of frost-riven rock fragments, quite 
unlike all the other mountains of New England, excepting 
the higher part of the range that culminates in Mt. Washing- 
ton, whose top will be remembered by all who have visited it 
as having this character. So remarkable is this feature that 
the ledges fractured by frost at the summit of Mt. Wash- 
ington are illustrated in the heliotype frontispiece of Vol. L 
of the "Geology of New Hampshire." The same condition 
is found by Dr. George M. Dnwson on the upper part of the 
Three Buttes, or Sweet Grass hills, in northern Montana, 
which rise 6,200 to 6,483 feet above the sea. These hills stood 
more than 1,500 feet above the surface of the ice-sheet ; for 
they bear bowlders of the glacial drift in abundance up to 
4,600 feet, but no fragments of foreign origin could be found 
more than sixty feet above that bight.* Along the range of 
the Rocky mountains, also, in Colorado, as I am informed by 
professor C. E. Fay, frost-riven fragments generally cover the 
bed-rock on all slopes that are not too steep to allow them to 
accumulate ; and this is finely exhibited in an extensive series 
of photographs made by Mr. F. H. Chapin, in hi.s mountain- 
eering in that region. 
New England presents three types of mountains in respect 
to glaciation, of which the least frequent is exemplified in this 
district only by Mts. Katahdin and ^^'ashington, with neigh- 
boring peaks of the Presidential range, where the surface has 
not been swept by the current of the ice-slieet, or, if it was at 
■ Memoirs of the Boston Society of Natural History, lStj.5, vol. i. 
•"• Geolopifal ami Natural History Surv(\v of Canaila ; Report of 
Progress for 1SS2, ISS:?, 18S4; and Annual Report 18b5, vol. i. ..i.^ 
♦ Ibid. : Report of Progress for 1882, 1SS3, 1S84.: Zim.,^ 
