30 
The Queensland Naturalist 
July, 1929- 
NOTES ON THE FOSSILS FOUND ON THE 
EXCURSION TO DARRA, 13th APRIL, 1929. 
(By Dr. F. W. Whitehouse.) 
The party visited the main pit of the Queensland 
Cement Co., where shaly clays of Tertiary age are well 
exposed. The beds form part of a considerable extent 
of tertiary deposits which were laid down in a lake, or 
series of lakes, occupying depression in the Lower Meso- 
zoic Coal Measures of the Brisbane-Ipswich district. These 
Tertiary beds in the Ipswich and Redbank Plains district 
have been divided into a lower Series (the Redbank Plains 
Series) and an Upper or Silkstone Series. These two 
series are separated from one another by flows of basalt. 
The sediments art* mainly sands, clays, and shales, with 
some freshwater limestones in the Silkstone Series. The 
Darra beds probably belong* to the lower or Redbank 
Plains Series . 
Fossils are abundant in many areas. The remains of 
fish, turtles, insects, and both univalved and bivalved 
molluscs have been found, as well as a wealth of fossil 
plants, mainly in the form, of impressions of dicotyledonous 
leaves. No systematic work lias been done on any of these 
groups except the insects in which group Dr. Tillyard 
lias recognised three species. Until much more work has 
been carried out it is impossible to place the beds in their 
proper position with the Tertiary period. 
On this occasion at Darra a large number of fossil 
plants and shells were obtained. The shells were all of 
fresh water bivalves probably belonging to the genus 
Unio or some similar form. Most of the plants 
collected consisted of impressions of dieotyledenous 
leaves: but one or two fragments were obtained 
which are probably the remains of ferns. The 
latter differed in .their preservation from the 
dieotyledenous leaves, in that they occurred as carbon- 
aceous films and not merely as impressions. The whole 
assemblage is very similar to that found in the beds 
exposed at ITurworth’s • Quarry on the main road at 
Oxley. 
Specimens of the Darra fossils as well as fish and 
other forms from the Tertiary beds of other areas, are* 
exhibited. 
