GEOLOGICAL FORMATION. 



201 



They are green with verdure and a full growth of tropical vegetation, which crowds np the 

 acclivities of the hills, from the very borders of the shore, whicli is, here and there, edged with 

 coral reefs. The headlands and detached rocks have been thrown by former convulsions of 

 nature into various grotesque forms, which assume to the eye the shape of castle and tower, 

 and strange animals, of monstrous size and hideous form. Numerous canal-like passages were 

 observed opening in the sides of the rocky cliifs, which had almost the appearance of being 

 hewn out witli the chisel, but which were evidently formed in the course of volcanic changes, 

 when the rock flowed in liquid lava, and found issue in these channels, which the torrents that 

 come down the sides of the mountains in the rainy season toward the sea have worn smooth by 

 constant attrition. Some of tliese dykes, or canal-like passages, less affected by time and the 

 washing of the water, still retain their irregular formation, which has so much the appearance 

 of steps that the observer^ as he looks upon them, might fancy they had been cut by tlie hand 

 of man in the solid rock, for the purpose of climbing the mountain. On the Southern Head, as 

 it is called, within the harbor of Port Lloyd, there is a very curious natural cave or tunnel, 

 which passes through the basaltic rock, from the Southern Head to the beach on the other side. 

 The entrance has a width of about fifteen feet, and a height of thirty, but the roof within soon 

 rises to forty or fifty feet, where it has so much the appearance of artificial structure, that it 

 maybe likened to a builder's arch, in whicli even the keystone is observable. There is sufficient 



Natural Tutinel, Port Lloyd, Bjnin I.~lands. 



water for a boat to pass from one end to the other. There are several other caves or tunnels. 

 one of which is at least fifty yards in length, and passes througli a headland bounding the 

 harbor. This is constantly traversed br the canoes of the inhabitants. 



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