( 8o ) 
As soon as the highest point of the mountain was passed by 
the advancing ice, more and more ice was forced over the top of 
the ridge, that extends southwesterly from the peak, and finally 
the ice passed around its southern extremity. The deflection to 
the eastward at the south end of the mountain was caused by the 
difference in the pressure of the ice on the east and on the west. 
The ice was crowded around the mountain to fill up the depres¬ 
sion under its lee, resulting because only a portion of its total 
thickness had passed over the summit. At the southern end of 
the mountain the direction of the striations is at one point S. 6o°E. 
The mountain as a whole seems to have had the same effect 
upon the moving ice, as a similar-shaped and submerged dam 
would have upon the waters of a somewhat rapidly moving stream. 
In the case of the stream, there would be quieter water under the 
lee of the dam, and like conditions appear to have existed in the 
ice stream under the lee of the mountain. The rocks there are, 
so far as observed, not embossed nor striated. 
Besides the main deflection of the ice by the mountain, local 
deviations were caused by comparatively small irregularities of 
the surface. This is perhaps best seen on Ragged Mountain, 
which, as the name implies, includes several peaks. The highest 
one is on the east. It is not possible to show all the smaller de¬ 
flections excepting on a map of very large scale, but some of 
them are clearly enough indicated on the map before you. For 
some distance west of the highest summit the courses of the striae 
are more southerly than they are on the summit itself, excepting 
in the depressions or saddles between the different peaks. Here 
the effect of the elevation on the west sometimes overcomes, locally, 
the general westerly deflection. As we travel along the ridge, which 
curves around to the southwest, the striae point more and more to¬ 
wards the east, but every little eminence has had its effect in produc¬ 
ing a local deviation of the ice current. In the saddle between 
MountKearsarge and Black Mountain, the deflection, here easterly, 
amounts to ten or fifteen degrees as compared with that of the un¬ 
impeded ice current over the summit of Kearsarge. On the hill east 
of Bradley pond (southeast of Andover Centre), there is a like 
difference in course between the striae on the summit and on the 
north flank. The striae in the valley of the Blackwater, near 
