The top of the rock is covered with a thick brush of Acacia leucophoea (of Lacrosse Island) many trees of which were obliged to be cut down or cleared away before the various objects could be seen from the theodolite.

Mr.Cunningham collected here specimens of eighteen different sorts of plants.
Bat Island is a mass of sandstone superincumbent upon a quartzose basis and intersected by nearly vertical veins of white quartz, the surface of which was in a crystallized state.

The floor of the cavern was covered with heaps of water-worn fragments of quartzose rock, containing copper pyrites, in some of which the cavities were covered by a deposit of greenish calcedony.

The sides of the cavern had a stalagmitical appearance but the recess was so dark that we could not ascertain either its formation or extent; it did not however appear to be more than twelve or fourteen yards deep.

On first entering it we were nearly overpowered by a strong sulphureous smell which was soon accounted for by the flight of an incredible number of small bats which were roosting in the bottom of the cave and had been disturbed by our approach.