96 THE HAWKESBURY SANDSTONE. 
conglomerates must occur at the base of the series ; but deren’ 
Rounded pebbles are certainly found all through the series from — 
bottom to top, but the conglomerates occur prin cipally in the upper — 
most portions. Our former distinguished Vice President (the late - 
Rev. W. B. Clarke) mentions this fact in the e quoted | 
Mr. Tenison-Woods at the commencement of his paper} ‘and Darwia 
also states that the pebbles increase in number and size in the 
upper beds. I have examined many sections of the Hawks 
table before you. I also exhibit specimens of the co 
m the Woolloomooloo quarries, as they well show the different 
kinds of the large pebbles, as well as the angular ar fragments of 
shale. As you approach the.western margin of the Hawkesbury — 
formation, near Marulan, you will find the upper sandstone 
gradually pass into massive pebble conglomerates of ea 
ness. This is just what we should expect to find o , 
of an old estuary or lake. In the cliffs at Bondi, and elsewhere 
about Sydney, you may see small beds, 3 feet thick, of 
conglomerate. In their mode of arrangement the pebbles 9% 
plainly seen to have been deposited by aqueous agencies. 
Conclusion 8. “The precipitous cliffs of the Blue ot 
the hard central cores of sandhills, the loose portions of hs 
have been easily blown or washed awa e orizontality of is. 
the beds and their structure, which I have already doen 
stone, and the sloping surfaces of the underlying 
where exposed, plainly indicate the nature of sca i a 
views have foie ate published in the “ Ne 
Railway Guide-book,” I will not enter upon 
present time. 
Conclusions 9 and 10.—“That in all respects the candstont 
like many desert formations of the interior,” and «That 3 * 
and arid or desert re. has existed in Australia in Mee 
é the Hawkesb bury formation, then, » 
Fe of formation, I very much qt 
