93 
deal more country, in which no traces of its presence have been 
preserved. 
Subsequent to the laying down of the Cretaceo-Tertiary lime- 
stones there have been further oscillations upward and downward 
of the land forming this State, with formation of the Tertiary to 
recent coastal limestones and sandstones. There is much doubt as 
to the thickness of these sediments, as some of the bores into them 
which appear to have gone to depths of 1000 to '1000 feet without 
getting through them are regarded by the Geological Survey as 
being in Mesozoic strata in their lower portions. The elevation to 
which they reach is also not at all certainly ascertained. On the 
Ravensthor])e Range near Kimdip. there are patches of probably 
rather recent conglomerate at quite <S0t) feet above sea level, and if 
some of the recent sedimentary dc])osits at Collie, overlying the coal 
measures, near Kirupp, and at Greenbushes are taken to belong to 
the coastal formation (Tertiary to recent) they would indicate 
marine or lagoon deposition at a horizon now elevated 700 to 
900 feet above the sea level. Here again it is im[)robal)le that the 
few relics still surviving of these beds would indicate the extreme 
height up to which the waters of the sea may have invaded the 
country, and it might quite well be that the subsidence of the land 
was great enough to flood the plains of the goldfields. It is sub- 
mitted that as there is proof up to ati elevation of 900 feet of 
subsidences sufficient to cause formation of probably marine sedi- 
mentary de])osits there is no great assunqgion involvetl in su])posing 
that they went on to a still greater extent so as to l)e sufficient to 
cause the sea to invade the interior at levels considerably above 
that elevation, and enough to impress upon the surface those 
features of marine planation which we now find to be characteris- 
tic of the goldfields landscapes. The subsequent elevation of the 
land would then lead to the formati<.)n of numerous salt lakes in the 
depressions of the generally flat surface, whether such depressions 
were due merely to inequalities in the level of the sea bottom or 
to slight deformation basins forming in the bedrock itself in the 
course of its elevatory movement. Some such unequal movements 
of portions of the upheaved block would lie only what might be 
expected during a continental movement of elevation. Signs of 
such uneven motion arc not wauling. A small fault, for example, 
has l)een found in the Siberia deep lead, throwing down the old 
gutter some six or eight feet, and at Coolgardie there is a very 
interesting patch of deep ground, about 400 feet deep, of probably 
Tertiary or Posl-'I'ertiary age, which seems inexplicable unless it 
is a small sunken field or "grave” where a wedge-shajjed piece of 
ground has been faulted downwards. It is not unlikely that such 
faults in the sui)erficial sedimentary deposits are quite common, 
and they may be the explanation of the apparent sudden cutting off 
at times of the "deep leads.” If there has been much faulting of 
this sort, however, there has been time since it occurred for all 
