SO-CALLED PORPHYRITIC GNEISS OF NEW HAMPSHIRE 713 
extension of the “fishhook” as in the southern part to which 
attention has been so far called. 
The porphyritic granite in contact with the Montalban group of 
schists—We shall not consider in this place the grounds on 
which the survey has separated the Lake Winnipiseogee gneiss 
from the Montalban group. Our field observations have shown 
us pretty clearly that, although the lithological characters of 
the two terranes may be on the whole different, any distinc- 
tion between them from a supposed difference of age is as yet 
without demonstration. Be this as it may, the problem before 
us can be solved without either proof or disproof of such a 
contention. At many points along the contact, the schists of 
the Montalban group are intersected by apophyses from the 
porphyritic granite, and appear as inclusions in the latter rock. 
The evidences of an intrusive origin for the porphyritic granite 
are of the same nature as in the case of the Lake Winnipise- 
ogee gneiss, and are just as conclusive. 
The Montalban group and porphyritic granite come in con- 
tact along the line running from Long Bay to Great Bay, and 
about one half mile east of Great Bay. Here a number of 
well-marked horses of the neighboring Montalban gneisses 
occur in the porphyritic granite. They possess a thoroughly 
gneissic structure, being as well foliated as their parent mass less 
than a hundred yards away. In this case the horses are not 
elongated and do not show any definite relation of position, 
either to one another or to the main contact line. Apophyses 
of porphyritic granite were also discovered along this part of the 
boundary. 
An interesting occurrence of the gneiss appears in the road 
on the north side of Shaw’s hill. It is isolated and completely 
surrounded by porphyritic granite whose nearest molar contact 
is nearly a mile away. This great horse is highly schistose, and 
several tongues of the granite here and there cut across the 
structure planes. The development of garnets in the horse may 
hint at some degree of contact metamorphism. 
A second large horse which is some distance from its parent 
