178 'R. ETHERIDGE, T. W. E. DAVID, AND J. W. GRIMSHAW. 
can be proved to have undergone in the past, and is probably still 
undergoing in the present. ; . 
Whether the change of level at Shea’s Creek be due to the 
movement of the land or that of the water is uncertain, but there 
is evidence, at all events, of an alteration in the level of the land 
and sea in recent geological time to the amount of about fifteen 
feet, as the trees found in situ by us at a depth of fifteen feet 
below high water all belong to genera which do not flourish 
below the level of high tide. This is probably one of the most 
important pieces of evidence yet obtained in any part of Australia 
to prove submergence in recent geological time. 
With regard to the question as to whether the submergence is 
still in progress, the fact might here be mentioned that Mr. 
G. H. Knibbs, t.s., and one of the writers, with the view of 
possibly obtaining some evidence as to whether the coastal strip 
between the eastern escarpment of the Blue Mountains and Port 
Jackson is still subsiding, have levelled carefully across the hinge 
of the fold which forms the inland boundary of the depressed area. 
Marks have been cut in the rock, and Mr. Knibbs proposes to 
to relevel between the marks three or four times a year. Possibly 
some results may be obtained in the course of a few years, and 
might tend to throw light on the question, as to whether the crust 
is subsiding or the ocean rising in the neighbourhood of Botany 
Bay. 
(2) Evidence as to the Geological Antiquity of Man.—A second 
deduction, perhaps more interesting than the first, may be drawn 
from the Shea’s Creek section, with reference to the geological 
history of man in Australia. As already stated, the bones and 
skull of the Dugong exhibited, show conclusive evidence of having 
been hacked by human agency, the cuts being exactly of the kind 
as would be produced by blows from a blunt edged implement. 
such asa stone tomahawk. We may look upon it as an established 
fact therefore, that this Dugong was cut up and no doubt eaten 
by the Aborigines. We have been unable to obtain any evidence 
to show that the Aborigines in the neighbourhood of Sydney ever 
