OSTRACODS FROM SOME QUEENSLAND TERTIARY BASINS. 121 
bank of Marked Tree Creek, and the remainder are believed to have 
•come from outcropping shales also on this portion. 
Unfortunately, all the material that has been available for study 
is very badly crushed — even more so than that from The Narrows or the 
Petrie Series — and detailed micropalaeontological work has been 
particularly difficult. 
The species identified in the collection of samples, in order of their 
abundance, are : — Erpetocypris aequalis Chapman, 1935 ; Stenocypris 
lowmeadensis sp. nov. ; Cypridopsis compressa Chapman, 1935. 
Discussion. 
Prom our present knowledge, the ostracod fauna of the Baffle Creek 
Tertiaries seems to show a fairly close resemblance to that of the Redbank 
Plains Series. The known ostracod faunas of both these basins are 
smaller than that of either The Narrows Tertiaries or the Petrie Series, 
and in both the Baffle Creek Tertiaries and the Redbank Plains Series the 
forms Erpetocypris aequalis and Cypridopsis compressa are prominent. 
Since only three species have so far been identified from both of these 
basins, the similarity in their ostracod faunas is all the more marked. 
Although Erpetocypris aequalis and Cypridopsis compressa are known to 
be long-ranged forms, their common occurrence and the absence of 
several species found in The Narrows and the Petrie Series material 
show that the faunas of the Baffle Creek Tertiaries and the Redbank 
Plains Series are distinctly different from those of the above basins, and 
suggest a somewhat different geological age. It might also be mentioned 
that a recent examination of the Redbank Plains ostracod-bearing shale 
has resulted in the discovery of Stenocypris lowmeadensis in that 
material, so that this long, narrow ostracod also occurs in both the Baffle 
Creek Tertiaries and the Redbank Plains Series, but has not been found 
in The Narrows Tertiaries or the Petrie Series. 
Accordingly, from this similarity in their ostracod faunas, it seems 
likely that the Baffle Creek Tertiaries are approximately equivalent in 
age to the Redbank Plains Series. Although the ostracods themselves, 
in this case, do not give any information as to the exact age of these 
beds, it might be mentioned that Hills (1934), from a study of the fish 
remains, has concluded that the Redbank Plains Series is most probably 
of Oligocene age. It therefore seems that the Baffle Creek Tertiaries also 
are probably Oligocene in age. 
The referring to freshwater genera of the ostracods determined from 
the Baffle Creek Tertiaries has also further supported the concept that 
the basin is wholly a freshwater one. 
Finally, mention might be made of the fact that geographically the 
Baffle Creek Tertiaries and the Redbank Plains Series are centred about 
the same distance inland from the present coastline, while The Narrows 
Tertiaries and the Petrie Series, on the other hand, respectively are 
found adjoining and adjacent to the present coastline. 
PART IV. GENERAL CONCLUSIONS. 
Palaeontological work on the above ostracod faunas has clearly 
demonstrated their stratigraphical value. It has been possible to draw 
up a broad zonal correlation of The Narrows bores, and to correlate a 
number of the isolated Tertiary basins. The Narrows Tertiaries and the 
