SOKCAULILIEID LAOS AE NABH TTA” (EINEMS Ss (OVE INP EWE AAA ES BK ID ANE 
ents is also lost in some of the tongues of porphyritic granite 
which penetrate the fragments in all directions. There the 
minerals are pulled out in planes parallel to the walls of the 
intrusion. The source of the hornblendic inclusions was dis- 
covered within a hundred yards of the breccia. An unknown 
thickness of the hornblende-gneiss lies interbedded in the 
biotite-gneiss. This great breccia outcrops at several places 
through a distance of three hundred yards along the base of the 
mountain and is only one hundred yards from the massive 
terrane of the Montalban group, which is continuous all the 
way from Morgan Mountain. 
These occurrences of hornblende-gneiss in the porphyritic 
granite throw light upon the ‘‘hornblende rock ” which was noted 
by Hitchcock in the Survey Report* as occurring to the east of 
Wickwas Pond. It covers altogether about an acre in extent. 
The rock is a hornblende-gneiss closely related in composition 
to the masses already described. It has a strong schistosity 
which lies parallel to the foliation of the granite enclosing it. 
The latter sends intrusive tongues into the gneiss which is 
evidently a large floe of the country rock moved far from its 
original source. 
The small oval area of the porphyritic granite on the top of 
Mount Prospect is a stocklike body which suggests from its 
position an intrusive origin. Field study confirms this opinion. 
The rock is typical of the porphyritic granite in composition, in 
grain, and in the size of the phenocrysts. Within this por- 
phyritic granite there are embedded several horses of the sur- 
rounding Montalban schists. The latter are extensively crum- 
pled, perhaps by the intensity of the granitic intrusion. Again 
one can notice the parallelism of the phenocrysts to the margins. 
The porphyritic granite in contact with the Rockingham muica- 
schist— One of the most important localities in the state to 
suggest an intrusive origin for the porphyritic granite is on 
Saddle Hill, where that rock comes in contact with the Rock- 
ingham mica-schist. Here the formation is composed of well- 
tVol. II, p. 594. 
