'895-] 503 [Tilton. 
There seems little reason to doubt that this rock is to be 
classed with the basin rocks. It is similar to other rocks to be 
found in various parts of the basin, and forms less conspicuous 
hills, as in the basm area generally, m contrast to the higher and 
more rugged hills of the surrounding granite area. 
The second region requiring special attention lies just north- 
west of Farm Pond. Here the outcrops are the exposed parts of 
a ledge extending in a northeasterly direction for a quarter of a 
mile. The exposed rocks have suffered so much metamorphism 
that their exact derivation is not ascertained with certainty. 
They may have come from felsite arkose or from felsite 
breccia, thus may be either of a sedimentary origin or the 
dike equivalent of a granite. 
A mile to the northeast, in the direction of the strike of one 
set of pressure-planes, a ledge similar in character to that just 
mentioned juts out from a granite area and extends southwest- 
ward toward the first mentioned ledge. Between these two 
ledges there is, toward the north, a large swamp, and toward the 
south, hills of drift (kame) ; but no outcrop of a rock that is 
undoubtedly of sedunentary origin. Yet, to the southeast of this 
line lie two ledges of conglomerate : one northeast of Farm 
Pond, near the river, the other southeast of Farm Pond, also 
near the river. Northeast of the latter is a line of angular 
conglomerate boulders for a quarter of a mile, though in no place 
is the face of a ledge to be discerned among them. These two 
ledges and a small area of clastic rock east of Farm Pond, form, 
with the outcrop of breccias near Morseville and South Xatick, a 
broken line extending between granite areas toward the conglom- 
erate north and northeast of South JSTatick. If the rocks north 
of Farm Pond were of undoubted clastic origin, this narrow area 
would stand connected with the breccias near MorseviUe; but the 
rock ma}^ be of igneous origin, in fact is better so explained not 
only in its microscopic structure, but also in its relation to the 
granite lying west. 
Xo contact is to be discerned between the breccia and the 
granite, at least in this part of the line. Even if there were, it is 
not hkely the contact would indicate the general position of the 
dividing hne ; but in other paits of the basin where contacts 
