Notes on the geology of Maria Island

These notes are intended as an incentive to future study rather than as a complete record of the geology of this interesting locality. They are the result of several holidays spent on the island, and particularly of two yachting trips undertaken recently. In many places the record is meagre, as I was unable to land and examine the rock formations in detail, but had to rely on observations made while sailing along, often in somewhat troubled waters. Still the description is complete enough to be of value, especially as no previous record has been made, with the exception of the late R. M. Johnston’s description of the Fossil Cliffs in his Geology of Tasmania. There is brief mention of a paper read by him before the Royal Society on Riedle Bay, but unfortunately it was not printed and his valuable observations have been lost.
Maria Island is situated on the East Coast, almost opposite to Spring Bay and Orford. The passage between it and the mainland varies in width from three to eight miles. In the narrowest part, off Long Point, is Lachlan Island, a small diabase rock covered with sparse vegetation.
Maria Island is one of those curious "tied-islands" to be found in Tasmania. The reason for their formation has not yet been determined, though it is usual to ascribe it to the sinking of the land, and, though not sufficient data has been collected to dogmatics on the matter, there is no reason to suppose that there have been any other forces in operation.