100 
second conglomerates and the first melaphyr, and terminated 
by the granite on the west shore, is bounded on the precip- 
itous northern side, as previously stated, by a fault, which, as 
the map shows, coincides with a dike (30). The dike can only 
be traced about half-way to the N. E. — S. W. fault, passing 
under the grass; but both the dike and its displacement un- 
doubtedly continue until the faults meet, as mapped. This 
dike-fault and the part of the N. E. — 5. W. fault northeast 
of the junction may be regarded as one continuous fault, 
with the downthrow on the north. That it is an important 
displacement is evident from the fact that the rocks north of 
this line are wholly different from those south of it. There is 
first a broad area of non-jaspery conglomerate — а normal 
puddingstone — sloping gently to the southeast and dipping 
in the same direction 5°-15°. It forms the eastern shore for 
about 100 feet; but the true thickness of the bed probably does 
not exceed 25 feet. This conglomerate is underlain con- 
formably and very clearly by typical, basic, green, amyg- 
daloidal melaphyr, which is identical with that on Melaphyr 
Peninsula and Melaphyr Plateau (Fig. 13). . The melaphyr 
outerops broadly around the conglomerate and the exposures 
of the contact are all that could be desired. The contempo- 
‘ancous origin of the melaphyr is sufficiently demonstrated by 
the fact that near the base of the conglomerate, especially, it 
encloses many water-worn fragments, from three to eighteen 
inches in diameter, of exactly the same kind of melaphyr. The 
melaphyr plainly consists of two flows, each of which is amyg- 
daloidal above and compact below, with an aggregate thickness 
of forty or possibly fifty feet; and this fact seems to identify 
it with Melaphyr Peninsula, and with the upper flow in the 
Crescent Hill section — the third melaphyr. — If this correlation 
be made, the displacement along the dike-fault can scarcely 
fall below 200 or 250 feet. 
The east-west fault crossing the summit of the. hill, with a 
southerly throw of ten feet, is very clearly exposed on the west 
