Geology.] 
NATURAL HISTORY. 
621 
appearance of calcedony, and is harder than ordinary car- 
bonate of lime. 
The characters of the shells in Captain King’s specimens 
from this place are indistinct; but the specimens at the Jardin 
du Roi, which, there is reason to suppose, have come from this 
part of the coast, contain shells of several species, — belonging 
among others to the genera, corbula, chama, cardium, por- 
cellanea, turbo, cerithium. M. Prevost, to whom I am in- 
debted for this account, observes, that notwithstanding the 
recent appearance of the shells, the beds which contain 
them are stated to occur at a considerable height above 
the sea: and he remarks that the aspect of the rock is very 
like that of the shelly deposite of St. Hospice, near Nice. 
King George’s Sound, on the south coast, east of south 
from Cape Leeuwin. — Beautifully white and fine quartzose 
sand^ from the sea-beach. Yellowish grey granite, from 
Bald-head. Two varieties of a calcareous rock, of the same 
nature with that of Dirk Hartog’s Island ; consisting of par- 
ticles of translucent quartzose sand, united by a cement of 
yellowish or cream-coloured carbonate of lime, which has 
a flat conch oidal and splintery fracture, and is so hard 
as to yield with difficulty to the knife. In this compound, 
there are not any distinct angular fragments, as in the stone 
of Dirk Hartog’s Islands ; but the calcareous matter is very 
unequally diffused. 
A third form in which this recent calcareous matter ap- 
pears, is that of irregular, somewhat tortuous, stem-like 
bodies, with a rugged sandy surface, and from half an inch 
to an inch in diameter ; the cross fracture of which shows 
that they are composed of sand, cemented by carbonate of 
lime, either uniformly mixed throughout, or forming a crust 
around calcareous matter of a spongy texture; in which 
