380 
The easterly bores of the Kow Plains series show a marked thickening of 
the polyzoal limestones, whilst to the westward these beds become thinner 
and more sandy, ultimately passing into green sands, with a stronger Aldingan 
facies. 1 
The natural inference from these data is that the western deposits at the 
same geological horizon were formed under current action. They are purely 
terrigenous in character, with a rich fish fauna. The eastward series was formed 
in deeper water, or where the conditions were conspicuously tranquil and free 
from irruptions of sediment such as terrigenous sands and muds. The conse¬ 
quence of this is that they show a predominant polyzoal fauna. The almost 
entire absence of corals maybe accounted for by the presence of so much exces¬ 
sively fine calcareous sand formed mainly of foraminiferal shells, which would 
obviously tend to deter coral growth. In .the one case the sediments were 
gathered by current action ; in the other they consist of material which lived 
and died on the spot, the finer muds, when not foraminiferal, being formed 
of powdered polyzoa ground by the agency of the wrasses and other fishes 
"with strong mandibular teeth, evidence of such fishes being shown in the 
fossil lists appended. 
Making allowance for the boring tube penetrating two or more distinct 
groups at one run, the sequence of the strata is clearly proved in this set of 
bores. The next in ascending order is the series of beds of Kalimnan age, 
into which the Janjukian strata pass almost insensibly. These Kalimnan 
beds consist of shelly marls and sands containing a predominant bivalve 
fauna, and are more generally of a littoral facies. 
To the Upper Pliocene (Werrikooian) beds may be referred the estuarine 
sands containing undersized specimens of foraminifera of estuarine types, 
which are characteristically thin-shelled and therefore easily floated into 
shore-pools, as they are at the present day. In illustration of this, the bore 
tube has sometimes penetrated a deposit of an almost pure gathering of these 
shells. Estuarine and shallow water ostracoda are also of frequent occurrence, 
as well as the minute spines of spatangoid sea-urchins. 
The fossiliferous sands and silts are overlain by barren quartz sands and 
grits, sometimes replaced by a thick deposit of micaceous grey, angular sand. 
These beds are referred to the Pleistocene. 
Later Pleistocene and Holocene.—These stages are represented, firstly, by 
white, yellow and red sands, the two latter being ferruginous-coated quartz 
sands ; and secondly, by earth-coated sands with fibrous vegetable remains, 
at or near the surface. At several horizons we meet with thin to thick deposits 
of pinkish concretionary limestone, which in some instances have afforded 
evidence of the co-existence of land-shells, such as live in saline lakes at the 
present day. 2 
1 In connexion with the two different aspects of the Janjukian sedimentation in the Mallee bores it 
may not be out of place to quote Prof. B. Tate’s remarks regarding the South Australian distribution and 
relationship of the Mount Gambier polyzoal limestone and the Aldinga marls, (see Trans. Boy. Soc. S. Aust. 
Vol. XX., 1896, p. 115) :— 
“ The Eocene beds of the Mount Gambier district are entirely isolated from all the other Eocene 
deposits, not only by their position, far removed from all other places where outcrops occur, but also by 
their fauna, which, with the exception of polyzoa, is extremely limited, consisting of about sixteen molluscs 
and six echinoderms, many of which are widespread forms.” [No reference is made to the rich ostracoaal 
and foraminiferal fauna.] “ However, by the wells at Bordertown and Pinaroo, we see the probable 
continuity of the Mount Gambier beds with those at Overland corner, while the four bores in the Ninety- 
mile Desert show that the same beds, at lower depth, join on to the Murray beds at Tailem Bend, and 
thus it is safe to say that the Murravian and Mount Gambier Eocenes are portions of the same deposit. 
“ Then also the similarity of the fauna of the sands met with in the Ki Ki bore with that of the 
Aldinga marls, would show that these two beds were deposited at the same time, from which we might 
infer that the polyzoal limestone which overlies the marls at Aldinga is contemporaneous with the similarly 
composed beds resting on the sands and clays, as shown in the accompanying diagram, and therefore 
with the Mount Gambier and Murravian deposits. Still, we see from the four bores above described that 
the line of separation of the sands and clays from the overlying polyzoal rock is very irregular, which 
tends to.prove that, although on the whole the sands are the older of the two beds, nevertheless they 
were being deposited at the same time in localities very near together, and that therefore local 
causes had a good deal to do in determining their deposition ; so that, considering how far removed are 
Aldinga and the Murray Cliffs, we might be making a mistake in saying that the Aldinga marls are older 
than the Murravian limestone, though this is probably the case ; and at any rate we may be fairly safe 
in concluding that no period of any length separated their formation.” 
2 See note at end of table, Bore No. 9, p. 353. 
