June 28, 1894] 



NA TURE 



207 



biological reasoning, that in the Lower Cretaceous period a 

 great part of Central Australia was covered by a sea which 

 extended from the Gulf of Carpentaria to the Great Bight, and 

 so divided the continent into an eastern and western moiety. 

 Following this, an upheaval of the sea-covered area took place, 

 succeeded by a dcnudaiion of the cretaceous deposits. Unequal 

 movements of depression then brought about lacustrine con- 

 ditions on portions of the now uplifted bottom of the old sea 

 strait and, in other portions, permitted of the admission of the 

 waters of the ocean. Finally a general upheaval, followed by 

 utter desiccation, placed the deposits of the period just con- 

 cluded in nearly the condition as that in which we now find 

 them. 



The systems of existing lakes, which have been mentioned in 

 an earlier part of this paper, are evidently the shrunken 

 remnants of the much larger lacustrine area of Pliocene times 

 — a condition which demanded for its existence a much greater 

 rainfall than now exists, and was contemporaneous with that 

 which gave rise to the glacial phenomena at places in more 

 southern latitudes in .Australia. The region of Lake Eyre was 

 then, as now, the centre of the inland continental drainage. 

 Towards this depression are directed many dry water-courses, of 

 which those of the Macumba, Finke, Cooper, and Diamantina 

 are the chief. For miles around extends an area of sand-hills, 

 separated by loamy interspaces, which are littoral sand-banks 

 marking the successive changes in the contraction of the waters. 

 Within its basin the Pliocene sands and loams have yielded 

 further proof of its lacustrine origin in the remains of 

 Diprotodon, Turtle, Crocodile, and Ceratodus. 



In Prof. Tate's opinion. Lake Torrens may have belonged to 

 a lacustrine area distinct from that of Lake Eyre, as with the 

 existing contour of the country a submergence of at least four 

 hundred feet would be necessary before the two systems could 

 be connected. 



Such a submergence would also unite in a vast inland sea the 



whole of the lake region around Lake Eyre and to the west- 



: ward of Lake Torrens. A very much less considerable sub- 



I mergence would connect Lake Eyre with Lake Frome and the 



■ lakes to the north of it. Much of the Murr.ay Desert to the 



tward of Overland Corner, and perhaps the whole Riverine 



4ion, w.as at this time a lacustrine area, though probably 



II connected from those of Lakes Eyre and Torrens. 



The following table, based on Mr. Hurst's report, and revised 

 by Prof. Tate, represents approximately the classification of the 

 I formations of the district : — 

 Recent. — Loose sand generally forming low ridges, sand-hills, 



or dunes overlying in places the Pliocene beds. 

 Pliocene. — Lake Callabonna ; fossiliferous formation. 

 1 Bands of unctuous blue clay containing abundant quantities 



of saline minerals and concretions of carbonate of lime ; 

 ' thin seams of sand ; inllorescent deposit of salts upon the 



surface. Fossils : Extinct Mammals, Birds, a fresh-water 

 Mollusk (/'^/a/«o/ij<r^«j, sp. ), Entomostracans, and a few 

 plants of living species (Cham and Callitris rolntsta). 

 Mesozoic. — {A) "Desert Sandstone" or Upper Cretaceous 

 (hard quartzites or porcellanized sandstone, gritty sand- 

 stones, and conglomerates). Fossils : Dicotyledonous 

 leaves. {B) " Rolling Downs" formation or Lower Cre- 

 taceous ; shales with fossiliferous limestone bands. 

 Azoic. — Metamorphic schists. 



Clay slates, mica, talc, and hornblende slates, metamorphic 

 and intrusive granite and greenstone. 

 The Pliocene formation in which the extinct Marsupials occur 

 does not appear to be restricted to the present boundaries of the 

 lake, since wells, sunk a considerable distance from tiie present 

 shore, have yielded fragments of bone in exactly the same 

 formation, thereby showing that the lacustrine area, in Pliocene 

 times, occupied a larger area than at present. 



The Mesozoic formation is limited upon the surface to a line 

 of outcrops along the eastern slope of the Flinders Range. At 

 Parabana, Pepegoona, Hamilton and Paralana Creeks, these 

 beds occur as the edges of an immense mesozoic basin which 

 underlies Lakes P'rome and Callabonna. The detritus of this 

 formation forms the stony table-lands and plains of the country, 

 and the, so-called, stony deserts of the early explorers have 

 their origin in the same formation. 



The Azoic rocks are restricted to the Flinders Range, and are 

 of doubtful age. These rocks were pierced by the Government 

 boring parly at Lake Frome several years ago, while boring 

 through the Post-tertiary and Mesozoic formations in search of 

 artesian water. 



Fossiliferous Area. 



The area that has been more or less well explored, is not 

 more than a mile long by about half to three-quariers of a mile 

 wide, but this forms but a small portion of the fossiliferous 

 ground. Bones were dug up at the springs lying in the lake 

 bed eight miles to the north of the camp, and were observed on 

 the surface in a very weathered condition all along the track 

 thither. In fact Mr. Zietz informs me that traces of bones and 

 teeth exist on the surface in almost every part of the lake he 

 examined. Nor, as has been saiJ, are they restricted to the 

 present boundaries of the lake. 



Surface Skeletons. 



One very remarkable feature is the existence of surface 

 skeletons, indicated by the presence of concretionary limestone, 

 or travertine, which has formed for the bones a sort of cast, 

 elevated a few inches above the surrounding level. In some cases 

 the relative position of the bones has been preserved to such an 

 e.xtent that the limestone mass presents a striking outline of the 

 form of the skeleton. Usually in such cases the animal is lying on 

 its side with the head and limbs plainly visible and more or less 

 extended. The actual osseous substance has, in many of the 

 bones of these surface skeletons, co'iaple:ely disappeared, but 

 not however, in all cases, some of them, usually the limb-bones, 

 are more or less imperfectly preserved and devoid of concretion. 

 Several of these surface skeletons existed near the camp at the 

 time of my visit, but Mr. Zietz informs me that after the drying 

 up of the rain which then fell they were no longer visible, 

 having been covered up by the general saline encrustation which 

 has previously been spoken of. 



Conditio.^ oi-^ the Bones. 



The condition of the bones varied very much ; some were so 

 friable that they crumbled into powder and could not be re- 

 moved ; others, usually in moist places, were wet, soft, and of 

 the consistency of putty. Curiously enough, for reasons which 

 are not clear, some bones from wet places were firm and hard, 

 while others from ground that was comparatively dry were 

 soft. .\s a rule, those in best condition came from localities 

 which, without being too wet, were moderately damp. The 

 bones, thus varying in condition and consistency, required very 

 dilTerent methods of treatment. The greatest difficulty was 

 undoubtedly due to the circumstance that the bones were 

 saturated with what was practically a concentrated saline solu- 

 tion. In fact, al! their cavities were so filled with this fluid 

 that it was necessary to allow a considerable time for it to drain 

 away. In other cases the bones were encrusted and impreg- 

 nated v/ith gypsum crystals. P'rom such causes the bones 

 became in dry wealher brittle and liable to break or crack, and 

 in damp weather dilTicult to dry. Very careful and patient 

 methods of treatment had consequently to be adopted, and will 

 still be necessary until the salt is removed. 



When dry, the fractured surfaces adhere strongly to the 

 tongue, and an approximate chemical examination, by Mr. 

 Turner, of a clean piece of Diprotodon bone gave the following 

 composition : — 



Substance dissolves almost entirely in dilute hydrochloric or 

 nitric acids. Contains — 



Moisture 376 per cent. 



Organic matter ... ... 7'4 .t 



Inorganic matter, mainly phosphate of 



liuie with some carbonate ... ... 8S'84 ,. 



Total 100 



Position and Attitude ok Skeletons. 

 The heads were pointed towards all directions, and the re- 

 mains of different animals frequently much mixed. Where, 

 however, the bones of an individual were lying in juxtaposition 

 they preserved fairly constant relations to one another. The 

 vertebra;, for instance, often formed a more or less continuous 

 series or were broken up into segments, of which the con- 

 stituents were in such close apposition that they could be 

 removed entire. These bones and .the head, which w.as often 

 much flatloneJ laterally, as if by pressure, were usually lying 

 either in their proper position with the dorsal surfaces upper- 

 most, or were turned over on their sides. The pelvis was 

 usually liorlzontal ; of the ribs, some were in situ, others either 

 widely separated from their fellows, or several firmly welded 



NO. 



I 287, VOL 50] 



