36 BULLETIN OF THE 
ever, the nearest approach to them being a slight rounding of some of 
the sharper corners and edges. It seems evident that these boulders 
have suffered none of that extreme abrasion which would have been 
caused by friction against the bed-rocks. 
It is probable, then, that the boulders of the trains were removed 
from their original*bed by the lower surface of the ice-sheet, and became 
imbedded in the mass of the ice instead of being dragged along beneath 
it. This supposition is in harmony with the observed sharpness of the 
knob called Fry’s Hill, the origin of the principal train, ‘sinee boulders 
torn from its upper part would be at least 100 feet above the lower sur- 
face of the ice-sheet along the neighboring parts of the crest, and the ice, 
closing together again as soon as it had passed the sharp knob, would 
hold many of them firmly without allowing them to work down to the 
rocks below. 
Two great deviations from the normal course may be observed in the 
boulder trains, especially in the principal one. If that part of the ice 
containing the boulders had met with no deflecting force, it would have 
preserved a rectilinear path in a S. 50? E. direction. The maxima of 
deviation from the normal course are on the western spurs of the Rich- 
mond Range, and on the western slope of the Western Branch of the 
Lenox Range, and they show by their positions relative to Perry's Peak 
and Lenox Mountain that these mountain masses were the obstacles 
which temporarily turned aside the boulder trains from their normal 
course. 
The second, third, and minor trains exhibit gaps, caused probably by 
the temporary failure of the ice to get hold of any of the rock material ; 
the tough schist resisted successfully for a time the efforts of the ice to 
tear it from its bed ; then a mass was obliged to yield to the prolonged 
strain, and, becoming loosened, the resulting fragments were borne away. 
The rock left behind, being still firmly fixed in its place, would in its 
turn resist for a time, thus causing another gap in the train, till in time 
another mass would be obliged to yield to the rending action of the ice, 
and so the process would go on. 
The sharper the knob the narrower the train to which it gave origin. 
This statement is well illustrated by the fact that the southeasterly 
parts of the second and third trains, which were given off at first when 
the knobs were sharp, are quite narrow and distinct, while the more 
northwesterly parts of the same trains, which were given off later, when 
the knobs had become somewhat rounded, are very much broader. 
A diminution in the size of the boulders towards the southeast has 
