4 
101 
Granite. Conglomerate. Melaphyr. 
FIG. 13.—A NORTH-SOUTH SECTION ACROSS Rocky NECK. 
SCALE, I INCH — 400 FEET. 
side, where it breaks the contact of the conglomerate and mela- 
phyr (Fig. 13). It is nearly parallel in direetion, but opposed 
in throw, to the fault bounding this hill on the north. The mela- 
phyr and conglomerate rise here in a sloping cliff of 20 to 40 
feet, extending the entire length of the hill and overlooking 
the small plain which forms the extremity of the Neck. 
The melaphyr north of this fault-scarp is similar to that south 
of it; but itis underlain on the west by a limited bed of con- 
glomerate, which, dipping S. E. 2*—5*, must abut against the cliff 
of melaphyr, although the contact is not exposed. This proves 
the fault, for the northern conglomerate, rising toward the west, 
could not otherwise fail to appear in the western half of the 
cliff. This conglomerate is of normal character, with an average 
thickness not exceeding ten feet. It is plainly cut on the north 
shore by a north-south fault, sinking the conformable contact 
with the overlying melaphyr about eight feet on the east. The 
conglomerate is, in its turn, clearly underlain on the west by a 
non-amygdaloidal melaphyr, of which about twenty feet are ex- 
posed at low tide. Superficially, at least, this melaphyr is highly 
brecciated, so that it is not quickly distinguished from the con- 
elomerate. It encloses numerous masses of compact melaphyr 
similar to the matrix, more or less rounded, and of all sizes up 
to eighteen inches in diameter. It is probably not a conglom- 
erate or tuff, but a very coarse original brecciation, something 
similar to the melaphyr holding the pseudo-bombs on the north 
side of Atlantic and. Centre Hills. The entire rock is similar 
in color and texture to the melaphyr of Long Beach Rock and 
