= 
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alone sufficient to prove that the conglomerate is newer than, 
and was deposited upon the granite ; although at first glance, 
or in a general view, the opposite relation might be regarded as 
well sustained, the conglomerate appearing as isolated masses 
enclosed in the granite. But an examination of the contact 
between the two rocks removes all doubt as to the true history 
of Granite Plateau. The conglomerate clearly rests upon the 
granite and fills the irregularities of its surface. Instead of the 
granite being intrusive in the conglomerate, the appearances are 
just the reverse, narrow cracks in the granite being filled, dike- 
like, with conglomerate and sandstone. These fragmental dikes, 
the roots of a once continuous bed of conglomerate, are exposed 
repeatedly along the shore, as well as over the surface of the 
plateau; and they seem to prove conclusively that erosion has 
eut just to the base of the conglomerate, clearly exposing the 
original granite floor, but leaving it essentially intact. It is very 
evident that the conglomerate was deposited over such a broken 
and fissured surface as the granite presents along our shore to- 
day. 
Besides the granitic débris, the conglomerate includes numer- 
ous pebbles of felsite and a large proportion of melaphyr, show- 
ing that voleanic action had been instituted in this region before 
the formation of this bed of conglomerate and hence that, al- 
though resting directly upon the granite, it is not the true basal 
conglomerate. Probably, as a rule, each successive bed reached 
farther inland, the overlapping edges, only, being in immediate 
contact with the granite. The conglomerate in the more south- 
ern outlier on the eastern edge of Granite Plateau is curiously 
involved with irregular masses of a compact eruptive rock, which 
can not be referred directly to either an underlying or overlying 
mass of lava but which proves on examination to be identical, 
lithologieally, with the first (ew to be described in other parts 
of the western area. The significance of its occurrence at this 
point, will be explained after we have studied the flow to which 
it is related. 
The granitic area south and southeast of the west marsh, 
