Conglomerates in New England Gneisses ■— Hitchcock. 253 
Mackenzie Valley we are as yet without any very definite in¬ 
formation, but Sir J. Richardson notes that Laurentian boul¬ 
ders are scattered westward over the nearly horizontal lime¬ 
stones of the district. 
Taken in conjunction with the facts for the more southern 
portion of the Continent, already pretty well known, the ob¬ 
servations here outlined would appear to indicate a general 
movement of ice outward, in all directions, from the great 
Laurentian axis or plateau which extends from Labrador 
round the southern extremity of Hudson Bay to the Arctic 
Sea; while a second, smaller, though still very important 
region of dispersion—the Cordilleran glacier-mass—occupied 
the Rocky Mountain region on the west, with the northern 
and southern limits before approximately stated. 
I have refrained from entering into any detail at this time 
in respect to the glaciation of the northern part of the Cordil¬ 
lera belt, as it is probable that within the year we shall be 
more fully informed on the subject, as the result of observations 
to be expected from Mr. R. G. M’Connell of this SurvejL Mr- 
M’Connell is now on the Mackenzie River, which, as well 
as the Porcupine branch of the Yukon, within the Arctic 
circle, it is intended that he shall examine during the summer. 
CONGLOMERATES IN NEW ENGLAND GNEISSES. 
|"A letter addressed to Alexander Winchell.] 
By Professor Charles IT. Hitchcock. 
Your paper upon Conglomerates enclosed in Gneissic Ter- 
ranes , in the March number of the American Geologist , brings 
out very important facts in reference to the origin of gneiss, 
particularly that in the older Archaean. My observations and 
studies have inclined me to doubt the presence of water-worn 
pebbles in the Laurentian or in granite, and I have been wait¬ 
ing to hear from those who have discovered them. The ob¬ 
servations of such a veteran in geological service as yourself 
should certainly be conclusive. 
You have made several references to localities in the east 
with which I am familiar, and I desire to say that I am inti¬ 
mately acquainted with them all and find nothing in favor of 
your proposition in them. To begin with, none of them are 
in the true Laurentian, so that, granting the presence of 
