195 
NOTES ON THE ORGANIC REMAINS OF THE 
OsSEOUS CLAYS AT LAKE CALLABONNA. 
By Proressor RarpH Tate. 
[Read September 5, 1893. ] 
The stratum in which the diprotodon and associated vertebrate 
fossils are found is a blue tenacious clay, though containing about 
12 per cent. of sharp quartz-sand, as determined by mechanical 
separation. Overlying the blue clay is a sand, which constitutes 
a fringe to the lacustrine plain, and appears as islets dotting its 
surface. Lake Callabonna is now a salt-pan, but is occasionally 
submerged, either as the result of heavy local rains or by the 
superfluous water of Cooper Creek, reaching it by way of Strze- 
lecki Creek and Lake Blanche. 
Anxious to learn something of the physical conditions which 
prevailed at the time when the diprotodons inhabited this area, 
I have minutely searched the clay and sand, obligingly placed at 
my disposal by Dr. Stirling and Mr. Zeitz, for their organic con- 
tents, with the following results :— 
The clay has yielded two cones of the smooth-valved form of 
Callitris robusta, RK. Brown, the living sandarach-pine, so widely 
distributed in Australia, and certainly an inhabitant of its “dry 
zone ;” oospores of characeous plants, probably of two species, 
one of which I refer with a doubt to Chara Brauniv ; fragments 
of a small gastropodous shell, probably of the genus Potamopry- 
gus. The charas and the mollusc are aquatic in habit, and may 
have endured a brackish water medium. The sand has furnished 
a new species of Blanfordia, B. Stirlingi, Melania lutosa, Cor- 
bicula desolata, which occurs in a living state in Cooper Creek, 
a cypris-like ostracod, and the charas above-mentioned. The 
Blanfordia is related to 4. striatula, an inhabitant of brackish 
waterpools on the coastal tracts of Southern Australia; but this 
alliance does not forbid a strictly fresh-water habit, which is im- 
plied by the association with Corbicula and Melania, though it may 
indicate an increased salinity of the lake-waters prior to their final 
dessication. Indeed, it is not at all improbable that all lived in the 
lake while its waters were fresh, that the Corbicula and Melania 
succumbed when the water became brackish, and that the Blan- 
Jordia was unaffected by the change, but became extinct through 
failure of the essential medium. The sand contains also small 
cylindrical tubes, about one millimetre diameter, which recall 
agglutinated-sand cases such as are constructed by some may- 
