— Ill — 



was quite dark and was explored by candle light. 

 The length and width of this portion is about 12 feet. 

 The floor is of fine clay or rather alluvium brought 

 by water from the surface soil of the island. It is very 

 damp. The roof is circularly flat, like a flat arch. Its 

 centre is about the height of 34 feet from the flour of 

 the cave. Excepting at the entrance, which, as above 

 stated, was not likely made by a portion of the cave's 

 roof falling in, the roof descends on all sides to the 

 floor, and the side walls on which it rests are not 

 exposed. On looking carefully at the roof it was seen 

 to consist of one stone. By far the largest portion of 

 it was still entire. The other was cracked in several 

 places. But the cracks were not wide, and their op- 

 posite sides fitted each other so well, and no one 

 portion descending beyond another, the idea of the 

 roof having been made of several stones was excluded. 



Conjectures and speculation as to how this arch 

 was formed of one stone, would be interesting, and 

 the solution no doubt be instructive. But into them 

 I will not enter any further than to state that the 

 arch of one stone was likely the outside of a stream of 

 lava. The manner in which the outer crust of a lava- 

 flow hardens into rock in cooling, while the mass of 

 lava in the interior is hot, molten, liquid as water and 

 flowing rapidly, is well known. Or, when the lava 

 was still in a liquid state, the arch might, like a 

 bubble, have been blown out by gas, and kept by the 

 same agent in position until the lava cooled and 

 hardened into stone. In cooling, the lava would 

 contract and crack at some part and the gas or steam 

 which inflated the bubble would escape. 



It was resolved that a search for fossils, bones, 

 &o., should be made among the soft soil that forms 



