264. SURFACE GEOLOGY. 
BouLpERLESS AREAS. 
In New Hampshire no considerable regions are devoid of boulders, 
except areas of sand where the stones are concealed by deposits of later 
‘age. The nearest approach to a boulderless area is in the limestone 
regions of Cornish and Colebrook. In eastern Vermont the absence of 
boulders over the same formation is very conspicuous, as may be seen 
in passing up Wait’s river and the east branch of White river. The 
boulders of the underlying rock decompose readily, and it is believed 
that though once as common as the average of granite blocks in New 
Hampshire, they have been disintegrated by atmospheric agencies, leav- 
ing very few signs of glacial work. Occasionally lines of granite boul- 
ders occur in this calciferous area, enough to show that the glacier did 
not slight it. Such boulders would furnish excellent studies of the radial 
dispersion of fragments, as their distribution could be easily made out. 
On the contrary, some kinds of rock seem almost incapable of decom- 
position, and leave the fields profusely strewn with them, The porphy- 
ritic gneiss and the Exeter sienite areas are remarkable for the great 
amount of rough blocks of their own kind scattered over them. They 
are mostly those that have just started on their travels. Between Dover 
and Exeter the loose fragments of sienite scattered over the area occu- 
pied by this rock are numberless, and commence abruptly on the north- 
west side. One knows that he has reached the sienite rock by the 
numerous blocks of it seen long before a ledge can be found, it may be. 
I suppose their abundance is to be explained by their difficult decompo- 
sition. 
LarGE BouLDERS. 
Although our state is noted for the great abundance of boulders 
strewn over its surface, it is only quite recently that I have seen boul- 
ders in our limits larger than any of which mention has been made in 
the writings of American geologists. They were brought to our notice 
by His Excellency Governor Prescott. Regret had been expressed to 
him that no boulder had been found in the state equal in size to those 
known to exist in the neighboring states. As if he felt the credit of the 
state impaired by the imputation, he immediately searched the neighbor- 
