31 6 
Geology of Sydney. 
but the result of running water. Our final quotation 
is from the pen of the late Mr, Charles Wilkinson, 
whose writings, it is to be regretted, were all too few. 
He summed up the whole philosophy of modern 
Fig. S-t. -Narrabcon Shales exposed on the Coast 
to the north of Narrabeen. 
geology in relation to the power of rain and rivers 
when he wrote : — 
“The vastness of the depth and extent of the 
precipitous gorges and valleys of the Blue Mountains 
