74 
granite, lateritised on the top surface, almost perfectly flat on the 
top, and surrounded by plains probably quite 70 to 80 feet lower 
than the plateau. The cliffs or ‘'breakaways’’ forming the edges 
of the plateau are mostly very precipitous, and not easy to ascend 
except in a few places. They show all the characteristics of beach 
cliffs particularly well. (On the west edge of the plateau about V2 
feet down from the top in a sort of shelf in the scarp is the Wal- 
kinjerie rock-hole, well-known to travellers on the lOirrigrin road 
as carrying a good supply of water. The rock-hole catches the 
drainage from a fairly large surface of the flat top of the butte, 
but its occurrence where it is found, on the face of a precipice, is 
very unexpected and not very easy to explain. 
There are se\'eral possible explanations of this older plateau. 
It seems most probably quite considerably okler than the preseni 
plains, and it may well represent part of a i)cncplanated surface 
formed before the subsidence took ])lace which submerged the land 
and allowed a shallow sea to carve the present features. It is even 
rather likely that this surface was to some extent a reappearance 
of an immensely older one, on which the beds of the Nullagine 
series had l)een depositee], for traces of these are found not very 
far to the north of this region, and the big mass of them in Mt. 
Vagahong shows that they must have been a thick and extensive 
series. It is obvious that before the Nullagine beds were laid down 
the underlying old rocks must have been planed down and sub- 
merged. and wlien subsequent erosion removed the covering beds 
again it seem.s j)ossible that much of the old planaied surface might 
he uncovered without being itself much more deeply eroded than 
when previously a land surface, b'or the purposes of the present 
paper it is sufficient to regard this older plateau as part of an older 
land surface probably antecedent to the la.st submergence which 
mainly determined the existing relief. Tt may represent an older 
marine plain, possibly dating back to the subsidence which led to 
the formation of the Fuicla limestones. 
Further south there are frequent occasional traces of an older 
surface in outliers of lateritc and lateritic conglomerate found 
everv here and there lyitig on the old rocks in snch a manner as to 
show them to be merely relics of a much more extensive formation. 
One such isolated block — a small one — of ironstone conglomerate 
near Mt. Monger, was found to have been nearly undermined by 
alluvial gold diggers, the basal layer of the conglomerate contain- 
ing a little gold. The lateritic bods at Coolgardie railway station 
and the Coolgardie Hospital are a gootl example of this old super- 
ficial formation. Whether the auriferous sandstones and grits of 
Kintore are of this age or much older, is^at jireseiit quite an open 
(luestion ; they also are a relic of an older suiierhcial formation, 
mostly obliterated during the final carving out of the existing 
relief. 
