STRLZ ON MOUNT MONADNOCK. 
BY G. A. WHEELOCK. 
Havre in the last three years spent many days in studying the 
striæ on Mt. Monadnock, the writer is unwilling that the results of 
his observations should be lost for want of record, especially as 
they seem to have an important bearing upon unsettled questions 
of surface geology. This mountain is peculiarly favorable to such 
study. Its long spurs radiating from a central elevation, although 
less regular than the points of a star, yet present to four points of 
the compass long ranges of bare rock, which have recorded the 
markings of the ice period with all their variations of direction, 
and furnish a lesson not to be found, perhaps, in any other locality. 
To understand fully the meaning of the evidence herein detailed, 
it is necessary to have a clear idea of the relative bearing and 
position of these radiating ridges or spurs. 
For the sake of clearness of description we will suppose the 
principal ridge, which runs north 25° east, to be straight, and to 
be four miles long. This ridge was an uplift, sloping toward the 
west, and presenting its broken and precipitous face toward the 
east. It is like a dam set obliquely across the current of the 
northern drift, and its serrated edge rises from fifteen hundred to 
two thousand feet above the surrounding country, growing higher 
from each end toward its ventral parts. If we suppose 4 section 
of this range near the centre to be pushed some fifty rods farther 
west, and elevated to the height of three thousand two hundred 
and eighty feet, we shall have the summit of Monadnock. 
short spur projects west of the summit about a mile, and divides 
into two branches; these we will call the west and northwest 
spurs. The two ends of the dam we will call the north and south 
spurs; these with the western spur and its northwest fork com- 
plete the outline of the mountain, making four radii. : 
Numerous observations of the direction of drift striæ made m 
the adjoining towns show very general uniformity. They have ® 
range of not more than 15°, varying 15° west of north to north 
and south. On the summit of Monadnock the direction varies 
within the same limits. Only one set of striae were noted there 
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