THE BOTANY OF WESTERN AUSTRALIA. 251 
sort of indurated clay, coloured from ironstone, of a very barren des- 
cription. It is, therefore, evident that the extraordinary difference of 
the plants which clothe the surface of these hills must in a great 
measure be caused by the different nature of the rocks and soil of 
which they are composed. The Perongarup are clothed with mosses 
and Jungermannia and lichens, as rank and luxuriant as I have ever 
seen them in the moist, rich valleys in the south of Ireland. These, . 
as they grow and decay, lay the foundation of a soil which is covered 
with grasses and sowthistles equally rank to the tops of the hills; 
these, in their turn, furnish a soil which is covered with gigantic gum- 
trees, many of them 100 feet high, without a branch—by far the finest 
timber I have seen in any country. On the Toolbranup hills, from the 
porous nature of the sandstone rock, and the shifting, exfoliating nature 
of the slate, there is not a moss to be seen: there is therefore no soil 
formed for grasses to grow on. Over the whole of the sandstone part 
there is not a tree to be seen, and on the slate there are but a few 
stunted ones, in valleys near their base, and in gullies for a little way 
up their sides. Another striking example of the effects the soil has on 
ihe plants which clothe its surface, is to be seen at Cape Riche: the 
colony, with several others which are found only on the sea-coast. Mr. 
Cheyne's residence, on the east side of the cape, is on limestone, and 
near it he has most of the plants which grow on calcareous soil in 
this colony. But the most striking example of the effects of the soil on 
the plants which grow upon it, is seen at Mount Melville, a low iron- 
stone hill about half a mile from Mr. Cheyne's residence. This hill is 
the ** Collis Konkoberup " of the Plante Preissianz. To the many new 
plants found on this hill by Mr. Preiss, I have added many more. 
Here there is no difference of altitude, or difference of moisture; and 
itis very evident that the extraordinary variety of the plants which 
grow on Mount Melville and Cape Riche is solely owing to the different 
nature of the rocks which form these heights. 
Cape Riche, October 29th, 1848. 
