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227 
terminates upwards in layers of shales and slates, limestones, or perhaps 
in what is generally considered as the true argillite, when the limestone 
is entirely concealed. The slates and shales derive their interest by this 
connection with certain intertruded masses of igneous rocks. One of 
these, and it is the most remarkable of them, may be seen at Cannon's 
Point and at Whaling's Bay. At both places it is intertruded apparent- 
ly between the layers of slate. Its colour is pale reddish yellow, or 
yellowish red. It is a compact feldspar, in which are disseminated only 
sparingly small crystals of the same substance. It is therefore a por- 
phyry. That the mass is an igneous product there can be no doubt. 
The shales, however, in contact with it, are unchanged. It would there- 
fore appear, from this circumstance, that this mass of porphyry was 
protruded before the deposition of the shales, and that they were depo- 
sited upon and around the porphyry. In favor of this view it may be 
stated, that the shales are undisturbed in position » 
