No. 200. J 
229 
with bebbles, &c. Another locality of this variety of porphyry, occurs 
north of the High rocks at a place called the Rattlesnake den. This is 
in primitive rocks. Almost the whole escarpment which rises 200 or 
300 feet above the lake, is covered with fragments of the dyke which 
have fallen from the summit. I have just remarked that the shales were 
deposited on and around this porphyry dyke, and that they do not ap- 
pear to have been disturbed since their deposition, but an uplift of the 
shales have taken place at another point above and near Split rock, not 
far from which the whole stratum may be seen bent upwards by the 
elevation of the hornblende rock on which they repose, or against which 
they lean. The porphyry near Cannon's Point, occupies an area of 
some acres, crosses the road near the point and spreads out in the ad- 
joining fields. A beautiful dendritic variety occurs not far from the 
point on the west side of the road; it differs from common dentritic 
stone, that the surface exhibits no dendroidal markings, but the interior 
is decorated with beautiful infiltrations of colouring matter in the form 
of landscapes, trees, &c. It is probable that masses may be found which 
would form beautiful vases. 
The shales are also traversed by dykes of a different character than 
the one at Cannon's Point. The most remarkable locality is at Juni- 
per Island, south of Burlington. Fig. 15 is a view of a part of the 
Fig. 15. 
dykes cutting through the slate on this island. The two vertical dykes 
are the oldest; the other, which is nearly horizontal, cuts off the other 
two, and at the same time displacing them and crushing and deranging 
the layers of slate, a, Slate raised from a horizontal position; 5, the se- 
veral dykes. 
