53 
THE DHOWNEI) VALLEYS AND PLAINS, 
1'hat the land has l)een com])arative]y recently submerged (the 
third displacement above described) is at once suggested by the 
huge rounded masses of granite that rise boldly from the sea; by 
the irregular nature of much of the coast line; In the various sea 
channels: and by the full ap])carance of the rivers. 
Amongst the granite outcrops are the islands known as 
Breaksea. Michaelmas. Mistaken and Seal. These are either at 
the entrance to or within King (jcorge's Sound. On the mainland, 
the high and slee{) hills known as Mounts Melville, Clarence and 
Adelaide, rise sharply from the sea. and the same remark applies 
to the granite mass opposite Knm Point at the mouth of Oyster 
Harbour. Limestone Head at the southern entrance to King 
George’s Sound also shows a bold outline. It evidently consists of 
granite, coated with coastal limestone. 
The irregular nature of much of the coast line is shown by 
the large harbours frequently referred to in this paper, as well 
as by the smaller indentations to the cast and to the west. 
The various sea channels include the channel between Eclipse 
Island and the mainland, the three entrances to King George’s 
Sound, and the entrances to Princess Royal and Oyster Harbours. 
The former harbour { Princess Royal) originally apparently had 
three entrances, but the two southern ones have disappeared, owing 
to causes which are subsequently stated. 
The peculiar full appearance so indicative of drowned valleys 
is very well shown in the lower i^ortions of both the King and the 
Kalgan Rivers, the valleys of these streams in such portions con- 
taining far more water than they would if they acted merely as 
drainage channels for the ordinary rain waters falling within their 
respective basins. ( PI. II.. Figs. 1 and 2). 
These facts are therefore taken to be conclusive evidence of 
the recent drowning of the lower ])ortions of the valleys and of 
the plains on which the rivers formerly meandered. Thus the 
King and Kalgan Rivers were, prior to this drowning, united below 
their present mouths into one stream, which made its way over the 
land now covered by the waters of Oyster Ilarhour and King 
George’s Sound, and api)arcnlly ])assed through the notch that now 
forms the south channel of the Sound. By this submergence the 
rivers were betrunked and the three large harbours (Oyster. Prin- 
cess Royal, and King George’s Sound) were brought into existence, 
with probably however, at first an extension of the sea through 
to Torbay Inlet, with the long east and west Darwin Ridge as ai. 
island. Since drowning, various changes have taken place which 
have reduced the sea area, as will be shown in a later section. 
It may be noted that three channels form the entrances to King 
George’s Sound, and three channels (having the same east and 
