96 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
genus Eleocharis belongs, are rare as fossils in the early Tertiary, 
becoming more abundant in middle and late Tertiary times. This is 
quite a pertinent point in view of the fact that no sedges have been 
recorded from the Redbank Plains Series, which is probably of Oligocene 
age (Hills, 1934), while in certain horizons of the Petrie Series they 
have been found to be the predominating element in the fossil flora. 
Indeed, this alone is suggestive of an age for the Petrie Series younger 
than that of the Redbank Plains Series. 
It might be mentioned at this stage that the palaeobotanical study 
of Tertiary fossil seeds, has lately been found to afford a very delicate 
and reliable guide to stratigraphical correlation. This is of interest here 
because seeds of indeterminable plants have already been found near 
Bracken Ridge, and, if a sufficiently large number of well preserved 
specimens can be collected from this and other localities in the Petrie 
Series, a field for future research will be opened up, which may subse- 
quently prove of greater stratigraphical value than the isolated 
angiospermous leaves. 
Unfortunately, the several fossil Unionids found in the Petrie Series, 
are at present of no greater value as criteria of age than the plants. As 
a family of the Prionodesmacea, the Unionids are long ranged, extending 
from the i Triassic to Recent, but not becoming abundant till Cretaceous 
and Tertiary times. Moreover, no Tertiary fossil members of this family 
have yet been described from Queensland, although they have already 
been found in most of our Tertiary lacustrine basins. When a detailed 
palaeontological study of Australian Tertiary Unionids has been carried 
out, however, and the geological ranges of the various species deter- 
mined, our Queensland representatives should prove of stratigraphical 
value. In the meantime the two distinct species already found in the 
Petrie Series can only be compared with the recent forms, Velesunio 
ballonensis (Conrad) and Hyridella* australis (Lamarck). 
On the other hand, the ostracods collected from the Bald Hills, 
Strathpine, and Lawnton localities mentioned above have already proved 
to be of some stratigraphical value. Considered as a whole the ostracod 
fauna shows a very close affinity with that contained in the Tertiary 
shales of The Narrows near Gladstone. It might be mentioned here that 
E. S. Hills (1943) has recently determined, from a study of the fossil 
fish fauna, that The Narrows Tertiaries are younger than the Redbank 
Plains Series, and probably Miocene in age. The Petrie Series ostracod 
fauna, however, also shows some affinity with that from Redbank Plains, 
probably the most striking point being the - relative abundance of 
Erpetocypris aequalis. It must be borne in mind, however, that many 
of the simple, smooth-shelled Cyprids are long ranged, so that in evalu- 
ating the ostracoda as a criteria of age it is necessary to consider all 
members of the fauna. When this is done a much closer relationship 
becomes evident between the Petrie Series Ostracoda and those from 
The Narrows than between the former and those from Redbank Plains. 
However, as the writer is at present preparing a paper on the Ostracoda 
contained in various Queensland Tertiary deposits, which will 
incorporate a detailed account and description of the various species 
found in the Petrie Series, the above general statements only are made 
here. 
Only a small assemblage of fragmentary fish remains has yet been 
collected from the Petrie Series. However, as much of the material 
appears to be excellently preserved in bituminous shale, it might be 
