GEOLOGICAL FEATURES. XXXvii 
From the Cataract of the Macquarie, a flat ex- 
tends to the marshes in which that river ex- 
hausts itself. From the midst of this flat Mount 
Foster and Mount Harris rise, both of which are 
porphyritic : but as I have been particular in de- 
scribing these heights in their proper place, any 
minute notice of them here may be considered 
unnecessary. We will rather extend our enquiries 
to those parts of the colony upon which we shall 
not be called upon to remark in the succeeding 
pages. 
Returning to the coast, we may mark the geo- 
logical changes in a line to the S.W. of Sydney; 
and as my object is to extend the information of 
my readers, I shall notice any particular district 
on either side of the line I propose to touch upon, 
which may be worthy of notice. It would ap- 
pear that the first decided break in the sand- 
stone formation which penetrates into the county 
of Camden, is at Mittagong Range. It is there 
traversed by a dike of whinstone, of which that 
range is wholly composed. The change of soil and 
of vegetation are equally remarkable at this 
place ; the one being a rich, greasy, chocolate- 
coloured earth, the other partaking greatly of 
