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level plains near the banks of the Condamine River, where it appears to attain a depth 
of more than a hundred feet, as fragments of bones have been obtained at that depth 
in sinking wells. 
“ It may, however, be observed that, though the fossil drift is only found on the 
western waters in Southern Queensland, there are rich deposits in bone drift on eastern 
waters of Peak Downs in the central district. 
“ This alluvium is remarkably rich in fragments of bones of extinct animals, 
including Diprotodon australis. Macropus Titan, Thylacoleo, Phascolomys, Notothe- 
rium, &a. 
“ The bones are associated with fragments of shells of Unio and other fresh- water 
mollusca similar to those now found in the present watercourses, but more massive in 
structure, basaltic pebbles, sand and mud, the stratification of which indicates inter- 
mittent currents flowing down the present valleys, such as now result from the annual 
rainfall, but of much greater volume. 
“ Although the greater part of the bones are broken into fragments, and show 
evidence of being drifted and waterworn, there are some which prove that many animals 
cannot have been deposited before decomposition in the localities where their remains 
are now found grouped together. 
“ The general condition under which the bones are found indicates that what are 
now broad valleys and plains were originally extensive marshes with watercourses 
flowing westward into lakes, and that the gradual filling up of the lake-beds with drift, 
and the deepening of the channel of the Condamine River which drains the country, 
conjoined probably with a gradual decrease in the' annual rainfall, have combined to 
change a swampy country covered with coarse, weedy vegetation into open downs and 
plains producing short grasses totally inadequate for the support of animals with the 
heavy frames and peculiar teeth which characterised the majority of the ancient 
occupants of the district. 
“ There is no trace, either in the Darling Downs or any other part of Queensland, 
of any violent convulsion of nature which would be adequate to cause the total 
destruction of the Diprotodon and co-occupants of the country, and it seems most 
probable that their extinction re.sulted from a gradual change of climate and more 
effectual drainage through the deepening of the channels of the watercourses — aided, 
perhaps, by some slight changes of level. Pew satisfactory traces have been found of 
the vegetation of this period, though some fragments of what appear to have been 
woody seed-vessels are met with in the bone drift, but their condition is not sufficiently 
perfect to admit of any definite conclusions. The general character of the vegetation 
may, however, be surmised from the form of the animals, the structure of their teeth, 
and the mode in which they are worn by feeding on it. These data suggest coarse reeds 
and aquatic plants, such as would bo too succulent and liable to rapid decay for their 
preservation as fossils, while the absence of wood and ferns, which are so abundant in 
the older coal strata beneath, indicates that there was little or no forest. 
“ One remarkable feature of the older alluvium is that the fossil bones are only 
found in the detritus of the basaltic rocks. Alluvium of the same age, derived from the 
Carbonaceous and Devonian Series, have not as yet been found to contain remains of the 
extinct animals. This may Lave resulted from the superior fertility of the basaltic 
lands, which would be capable of producing abundance of food, while the comparatively 
sterile soil derived from the older formations wonld not furnish suitable vegetation for 
the sustenance of the massive quadrupeds of that era.” 
The occurrence of Diprotodon in the auriferous drift of Gogango Creek, near 
Rockhampton, is noted by Mr. Daintree in his “ General Report on the Northern 
