118 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
described and detailed accounts of the structure of the carapace valves 
have been given, however, no very definite comparisons can be made. 
The presence of Cypris and Cypridopsis in the material, unfortunately, 
is of no value for purposes of age determination, since, although both 
these genera occur mainly in the Tertiary, their ranges extend back to 
the Jurassic and the Permian respectively. The genera Erpetocypris, 
llyodromus and Cyprinotus, however, are of some value. They are found 
only in the Tertiary and Recent and neither llyodromus nor Cyprinotus 
appears to have been previously recorded from the Tertiary. 
Erpetocypris , however, has been recorded from the Redbank Plains 
Series, which is probably of Oligocene age (Hills, 1934), and the known 
backward range of this genus was thereby extended considerably. 
Accordingly, it seems most unlikely that the age of The Narrows 
Tertiaries is pre-Oligocene. The presence of more recent genera than 
are found in the Redbank Plains Series, in fact, strongly suggests that 
the age of the beds is post-Oligocene. However, since none of The 
Narrows species seems to be identical with any of the described recent 
Australian forms, it is improbable that the shales are of Upper Tertiary 
age, as Pliocene and Pleistocene ostracod faunas generally are identical 
with recent ones. Moreover, it has already been shown that certain of 
The Narrows species were short-ranged, and some members of the fauna 
are definitely known to be extinct. However, since all but one of the 
species described have been found to be new, it is apparent that the 
species themselves cannot at present provide more precise information 
concerning the age of the strata. 
All the above information seems to indicate a probable Miocene age 
for The Narrows Tertiaries. This agrees with Hills’ recent determination 
(1943), from a study of the fossil fish, that “the age of the strata is 
probably Miocene.” When more taxonomic work has been carried out on 
Tertiary and Recent freshwater ostracods, however, and the geological 
ranges of the various genera and species have been accurately determined, 
a more precise and definite age determination may be possible. 
B. Petrie Series. 
General Aspects. 
As mentioned above, ostracods have been recorded by Ball (1932) 
and the present writer (1944) from four places in the Petrie Series, 
where they were found in shales brought up on putting down wells and 
bores. 
The Petrie Series, situated just N. of Brisbane, was named and 
originally described by Jones in 1927, and a more detailed, supplemen- 
tary account was given by the present writer in 1944. The series occupies 
a roughly circular area of some fifteen square miles centred about 
Strathpine (14 miles by rail N. of Brisbane) and is made up largely of 
shales, which owing to their soft nature seldom outcrop. 
As well as the occurrence of ostrocods, unionids, fossil fish and 
various plant remains have also been found in this Tertiary basin and, 
on palaeontological and lithological evidence, a provisional Miocene age 
has already been given to the series (Beasley, 1944). 
