170 THE MEDALS OF OREATION. Cuap. VI. 
nearly related to the fruit of Araucaria excelsa, was dis- 
covered in the Dirt-bed. 
At Brook-Point, in the Isle of Wight, an equally interest- 
ing fact may be observed. At the base of the cliff, which is 
entirely composed of Wealden clays, shales, and sandstones, — 
there is a vast accumulation of petrified firs and pines, imbed- — 
ded in the indurated grit that forms the lowermost strata on — 
the sea-shore, and of whic: the reefs and rocks, produced by 
the encroachments of the sea, and that extend far from — 
land, are composed. These can be examined at low-water, — 
and the observer, upon lifting up the fuci and algze which 
cover them, will find the rocks and masses of stone to con- — 
sist of petrified trunks of coniferee. There are no erect trees 
as in Portland; on the contrary, the stems are prostrate, — 
and lie confusedly intermingled, and associated with bones — 
of Iguanodons and other reptiles, and large mussel shells; | 
the whole presenting the characters of a raft of forest trees — 
which had drifted down the stream of a vast river, and © 
entangled in its course the limbs and carcasses of animals 
that were floating in the water, and the shells that inhabited 
the river, and at length became submerged in the bed of — 
the delta or estuary. Both foliage and fruit have been © 
found in the Wealden deposits at Brook, and will be de- | 
scribed hereafter.* SW 
In the sands of the Desert of Sahara, in Egypt,—among — 
the mammalian bones of the Sub-Himalayas,—and in the ~ 
tertiary deposits of Virginia associated with cycads,—drifted — 
trunks of conifers have been discovered. 
Fossil trees of this family also occur in various localities — 
in Australia and Van Die men’s Land, the wood of which is 
in some parts calcified, and in others silicified. The 
same trunk often has externally a white friable calcareous { 
zone, several inches thick, traversed by veins of silex, or | 
opaline chalcedony, while the centre is a silicified mass; in — 
* See Geol. I. of Wight, chap. x. and xi. 
