SO-CALLED PORPAWRITIC GNETSS QF INEW HAMPSHIRE 777 
The Ashuelot area is even more nearly devoid of distinct 
zones of contact-alteration. Several suites of specimens were 
taken across the marginal belt of schists at several different 
localities, but in none of them was a definite alteration of mineral 
content observable, as one goes toward the igneous rock. While 
the Coés schists are highly garnetiferous at the contact, they 
are often just as metamorphic in habit a mile or more from the 
granite. Interlaminated actinolite-schists are abundant among 
the common mica-schists of the area. They show no change at 
the contact. The Bethlehem gneiss is often garnetiferous, and 
in some slides the garnets are seen to be larger and more idio- 
morphic near the granite than away from it. Apart from this 
fact, one would not suspect from an inspection of the marginal 
alterations that the porphyritic granite was once an igneous body 
intruded in these same rocks in a molten state. 
Finally, it would be difficult to point to any particular part 
of the Main area as exhibiting metamorphic phases in the schis- 
tose country-rock of the porphyritic granite which could not 
have been produced before the granite was erupted. One 
hundred and fifty feet from the great Greenfield sheet a typical 
quartz-garnet-hornfels can be found, but from that rock to the 
granite one passes over the typical biotite-muscovite-schist of 
the region. The latter itself may be garnetiferous. It does not, 
however, differ from similar phases of the ferruginous rocks 
several miles from the contact. North of Henniker there out- 
crops another hornfels at a contact with a prophyritic granite 
apophysis and about 50 feet from the molar contact. It is a 
compact aggregate of quartz and garnet with a large admixture 
of a colorless pyroxene and a little accessory plagioclase and 
muscovite. Notwithstanding this kind of association, these and 
other examples cannot as yet with safety be considered as con- 
tact phases, nor do they afford positive evidence of an eruptive 
origin for the porphyritic granite. 
The small amount of exomorphic change in the contact-belt 
is that which might be expected from the conditions of the erup- 
tions. It is well known that, other things being equal, acidic 
