PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA. 



571 



The fossils from Mount Macedon are less petrified than those from Darling Downs : 

 the osseous suhstance crumbles away if not supplied with gelatine, like the fossil bones 

 and tusks from our brick-earth in England. 



" Amongst the secondary hills which skirt the base of Mount Macedou there is a considerable circular plane, 

 which is more elevated iu its centre than at its circumference, and which will be better explained by a diagram : — 



A, A. Volcanic Hills surrounding the plain. 

 B B. The plain. 



c. A swamp or bog in which are found the bones at a depth of 4^ feet. After digging through a solid peaty 

 soil for 3 feet you then arrive at a stratum of gravel about 18 inches thick, in which the bones are deposited. 

 This layer of gravel rests upon a bed of firm clay, which is unfossiliferous. 



" The bog or marsh in which the bones are found is about four acres in extent, and appears to contain bones 

 at every point. I opened two pits at 150 yards distance from each other and found bones in both, in the same 

 stratum of gravel." — Letter dated January 1st, 1845. 



§ The following valuable Note on the formations of the locality accompanied the transmission of the fossils, by 

 the gifted and unfortimate explorer of that part of Australia : — 



" The DarHng Downs are extensive plains, formed by broad shallow valleys, without trees, covered only with 

 grass and herbage, which grows luxuriantly on the rich black soil, in which concretions of carbonate of lime are 

 frequently found. Eanges of low hills, forming long simple linos with sudden slopes and flat-topped cones, ac- 

 company these valleys, and have an open forest formed of various species of rather stunted Eucalyptus. All 

 these hills are formed by a basaltic rock, containing frequently crystals of peridote, and being often cellular, 

 sometimes real scoria. The base of the rock is, however, feldspathic ; and, as the peridote is frequently absent, 

 the rock becomes iiniformly grey, forms a white globule before the blowpipe, and is therefore to be classed 

 amongst the trachytes or phonolites. The plains are filled by an alluvium of considerable depth, as wells, dug 

 50-60' deep, have been sunk within it. The plains and creeks in which the fossU bones have been found are 

 ' Mr. Hodgson's Creek,' ' Campbell's Creeks,' ' Mr. Isaac's Creek,' and ' Oaky Creek." They pass aU into and 

 through immense plains on the west side of the Condamine, into which they fall. The bones are either found 

 in the bed of the creek, particularly in the mud of dried up water-holes, or in the banks of the creeks in a red 

 loamy breccia, or in a bed of pebbles, containing many trachytic pebbles of the coast range from the west side 

 of which these creeks descend. 



" In the banks of the creeks you find at first the rich black soil of the plain, about 3' thick, then layers of clay 

 and of loam, here and there, particularly at ' Isaac's Creek,' with marly concretions of strange irregular forms. 

 The masses of these concretions are often of considerable thickness, though not extending far horizontally. The 

 loam contains small broken pieces of ironstone (breccia) and is equally local. Below these the bed of pebbles 

 lies. The bones found in the breccia are generally near the concretions, but not with them, or they occur 

 amongst the pebbles. A very interesting fact is the presence of univalve and bivalve shells, which live stUl in 

 the neighbouring water-holes, in the same beds, in which the bones are foimd. They are either intimately 

 united with the bones by a marly cement, or they occur independently. The greatest depth in which bones are 

 found is 12'. At ' Oaky Creek' we found them at the surface. Besides the bones of the gigantic animal, there 

 are lower jaws and different parts of the skeleton of four other Kangaroos, many of them little different from 

 the living ones, and probably identical with those of Wellington VaUey. It seems to me that the conditions of 

 life can have very little changed, as the same shells live stUl in similar water-holes. The want of food can 



