13 
western area to be described later. If we make this correlation, 
then, since it is reasonably certain that other beds of melaphyr 
as well as conglomerate underlie the conglomerate of Round 
Hill, and we can not connect the latter with the basal conglom- 
erate on the granite; it appears necessary to suppose that an 
important fault, with the downthrow to the north, separates the 
granite from the hill,—a continuation with a different direction 
of the fault extending from Granite Point on Weir River Day 
southeasterly across Great Hill. 
The melaphyr on the southeast side of Round Hill is nowhere 
seen in satisfactory contact with the conglomerate ; but the slope 
of the hill on this side is nearly parallel with the bedding of the, 
conglomerate, and all the indications are favorable to the view 
that the melaphyr overlies the conglomerate conformably. This 
is the typical green and amygdaloidal melaphyr of the central 
area, and cannot be distinguished from that outcropping in the 
marsh. The flow-lines dip gently to the southeast, as do 
the bedding lines of the conglomerate. To the north, this bed 
of melaphyr approaches very near the southeast corner of the 
marsh, as already explained ; and we here reach the turning 
point of a marked and rather abrupt change in the strike of both 
the conglomerate and melaphyr. The normal dip of the Round 
Hill beds appears to be about east-southeast, and of the strata of 
Conglomerate Plateau and the district directly south of it, about 
south-southeast. 
The District between Round Hill and Hull Street.— 
This tract consists of rocky fields sloping southward from the 
escarpment marking the southern border of Conglomerate 
Plateau to the marshes of Lyford’s Liking. The melaphyr 
overlying the conglomerate on the southeast slope of Round 
Hil bends to the east, as already explained, to follow the 
southern border of Conglomerate Plateau. Dikes 40 and 41 
are evidently attended by some faulting ; and the narrow band of 
conglomerate in the melaphyr may be aecounted for in this way ; 
but whether it belongs to the conglomerate below the melaphyr 
