summit, was parallel to the direction of movement of the glacier. 
'Fhe striae everywhere on the ridge point towards the summit. 
Their courses vary from S. 36° E. to S. 43 0 E. On the summit 
they run S. 46° E. On the north side of the mountain, that is, 
on the east side of the spur, the New Hampshire geologists have 
noted a direction of S. j 6 ° E. and above this, and nearer the 
summit, I observed a S. 56° E. course. On the west side of the 
mountain, near its foot, strise have been noted having the follow¬ 
ing courses: S. 8° E. to S. 21 0 E. ; S. 9 0 E. to S. 3 0 W. and S. 
11° E. Platting these stria? on the map, we at once see that where 
the slope of the surface was opposed at right angles with the un¬ 
impeded ice current (shown by the striae on the summit), as it 
was along the axis of the ridge, it had no effect on the direction 
of the moving ice. For the ice was urged forward with such 
force that it overcame direct opposition and simply mounted the 
slope. But where the ice advanced diagonally to the plane of 
the slope it was more or less deflected away from the mountain. 
Thus on the northeast side of the ridge the striae have more east¬ 
ing and on the southwest side more westing, than on the ridge 
itself. The deviation appears to have been about the same in 
each case, for the planes of the two slopes made about the same 
angle with the direction of the advancing ice. One residt of the 
deflection of the ice by the ridge would, perhaps, have been to 
form wrinkles or corrugations, analogous to the waves formed by 
the prow of a ship, and in this case the forces acting to determine 
the direction of motion at the bottom of the glacier would be 
complex and probably variable. The direction of their resultant, 
along which the ice must at all times have moved, would then 
vary between certain limits. As a matter of fact the striations 
near each other on the ridge and on the summit are nearly parallel, 
while on the west slope, at all events, they often show considera¬ 
ble variation in course, on the same outcrop. For instance, the 
arrows joined at their feather ends on the map, below the Win¬ 
slow House, show the extreme courses, of the stride at these points. 
Many courses between the extremes are visible on the ledge—some 
crossing others. It would seem from the descriptions that crossed 
stride sometimes occur on the summits of mountains, where this 
suggestion that they are due to variations in motion caused by im¬ 
mediate topographical conditions would not apply. 
