115 
and then very recently this gap was filled up by a sandy material 
containing these shells, which are in a very good state of pre- 
servation. The relationship of these beds is shown on the 
diagram, representing a section along the railway line from 
Bordertown to Tailem Bend. 
The Eocene beds of the Mount Gambier district are entirely 
isolated from all 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, censisting of about sixteen molluscs and six echinoderms, 
many of which are widespread forms. However, by the wells at 
Bordertown and Pinnaroo, 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 
a 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 accompany- 
ing diagram, and therefore with the Mount Gambier and the 
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 con- 
cluding that no period of any length separated their formation. 
SUPPLEMENTARY NOTE. 
Since the above was written Professor Tate has examined 
fossils from the Eocene sands of the Ki Ki bore (380-424 feet 
below the surface) and has identified the following species and 
genera :— 
Terebratulina, sp. (prob. fry of T. Scoulari, ate). (passim). 
Crassatella communis, Zate. (passim.) 
