COASTS OF AUSTRALIA. 
53 
examination was found to communicate with i82i. 
Munster Water, and to insulate the land that July 30. 
forms the north-west shore of the bay: this island 
was called after the late Right Honble. Charles 
Greville, whose name has also been given to a fa- 
mily of plants {grevillw,) that bears a prominent 
rank in the botany of this country. The strait, in 
which the tide was running at the rate of six or 
seven knots, was not more than one hundred and 
fifty yards wide; but in one part it was con- 
tracted to a much narrower compass, by a bed of 
rocks that nearly extended across the strait, and 
which must originally have communicated with 
the opposite shore. 
We landed under the flat-topped hill, at the 
south end of Greville Island, among the man- 
groves which skirt the shore, and walked a few 
hundred yards round the point, to examine the 
course of the strait ; but the way was so rugged, 
and we had so little time to spare, that we soon 
re-embarked and returned into Half-way Bay. 
The geological character of the island is a red- 
coloured, coarse-granular, siliceous sand-stone, 
disposed in horizontal strata, and intersected by 
veins of crystallized quartz. The surface is co- 
vered by a shallow, reddish-coloured soil, pro- 
ducing a variety of shrubs and plants. 
After this we crossed the river, and examined 
