THE HAWKESBURY SANDSTONE, 103 
‘Tsand. If, indeed, any of our conglomerates were composed of 
coneretionary lu umps, I 5 ener Mr. Tenison-Woods’ theory 
80 far as se were in quest 
as to the cir of the beds. The general 
slope of te criginal ene from the base of those eminences, such 
as Mount t King Geo Mount Tomah, and Mount Hay, which 
ve been preserved fed denudation by their caps of basalt, down 
to the eastern esc carpment, is of course determined for us by the 
summit levels of the various ridges which remain as watersheds of 
general drainage. This slope, which is at the rate of 100 feet per 
nile, "dese all the appearances which would lead one to suppose 
as a plane of marine denudation. I am confident that no 
she contemplating it for the first time could come to any other con- 
clusion. ut, as Mr. Tenison-Woods justly urges, marine action 
isout of court.* The “ plane of marine denudation” must there- 
fore have its name erased from the evidence, in spite of its extreme 
Plausibility. And we shall be assured that no mistake has been 
made in this when we observe that the underlying coal measures 
Slope in precisely the same manner towards the same — 
Then the question occurs,—Were both formations constru ructed 
upon a pre-existing slope, to which their own bedding was accom- 
ted ; or has there been a general movement of ey in 
the west, ‘and depression in the east? I am certain examina- 
tion of the phenomena of the Hawkesbury valley that its bed must 
at one time—perhaps as far back as the period which we call Cre- 
'aeeous—have been several hundred feet above the sea, and that 
Within the Tertiary epoch it must have been at least 200 feet 
higher than at present. These considerations induce me to con- 
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; 
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es 
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<r = yeh are exceedingly interbating and riage 
. Sne, so far as: I am aware, oe previously pag ae to apply 
arg Hawkesbury rocks the tests of roundness and angu 
® distinguishi from wind 
tg at one time or other suffered attrition, or rather contrition, 
“om protracted periods of sand-drift. But though their 
