424 



NA TURE 



[March 3, 1892 



The following papers were contributed by Mr. J. B. Kirkland, 

 Assistant Lecturer and Demonstrator of Chemistry, University 

 of Melbourne : — (i) "Notes on the Electrolysis of Fused Salts 

 of Organic Basis"; (2) "Occurrence of the New Elements 

 Gallium and Indium in a Blende from Peel,wood, New South 

 Wales"; (3) " Notes on the Volatility of Magnesium"; (4) 

 " Lecture Experiment on Gaseous Diffusion." A paper on "The 

 Analysis of the Cavendish banana [Musa Cavendisliii) in Relation 

 to its Value as a Food," by W. M. Doherty, was also read. Profs. 

 Liversidge, Jackson, the President, Messrs. Clemes, Wilsmore, 

 and Taylor took part in an interesting discussion that followed 

 the reading of these papers. 



Papers were contributed by Mr. W. M. Hamlet on "The 

 Oleo-refractometer in Organic Analysis"; by Mr. A. H. Jack- 

 son on "The Analysis of Storage Battery Plates "; by Mr. A. 

 J. Sachs on " The Jarvis Field Mineral Waters of Picton, New 

 South Wales "; and by Mr. Mingaye on " Some Mineral Waters 

 of New South Wales." 



Mr. A. Liversidge, F.R.S., Professor of Chemistry, Uni- 

 versity of Sydney, read a paper on " The Rusting of Iron." It 

 was usually stated in books upon chemistry, he said, that iron 

 rust consisted of the hydrated sesquioxide of iron ; but on I 

 examining a very large number of specimens of rust from very 

 many different places, and from iron articles of various kinds, 

 and formed under very varied conditions, he found that in almost 

 every instance the rust contained more or less magnetic oxide ; in 

 fact, in some cases the rust, although presenting the usual " rust 

 brown " colour and appearance, was, when powdered, prac- 

 tically wholly attracted by the magnet. The specimens which 

 first drew his attention to the subject were some large scales of 

 rust obtained from the rails of an old tramway at Clifden 

 Springs, in Victoria, and he was led to collect and examine 

 these on account of their resemblance to the crust so often 

 present on metallic meteorites. On crushing this rust in a 

 porcelain mortar and testing it with a magnet, it was found to 

 be practically wholly attracted, the small quantity of iron 

 magnetic oxide present being mechanically inclosed, lifted and 

 removed by the magnetic particles (in consequence of the 

 magnetic particles being joined end to end, parallel to the lines 

 of magnetic force and forming a mesh-work inclosing the non- 

 magnetic matter); but by repeatedly applying the magnet, and 

 especially under water, the magnetic powder was fairly-well 

 separated from the non-magnetic powder. Bright iron wire, 

 plates, rods, nails, &c., were artificially rusted in many ways 

 with free access of oxygen, and in almost every instance a large 

 amount of magnetic oxide was formed. 



Prof. Liversidge also read a paper on "The Presence of 

 Magnetite in Certain Minerals." 



Some notes on the analysis of water from Lake Corangamite 

 were given by Mr. A. W. Craig and Mr. N. T. M. Wilsmore. 

 Notes on a "Natural Bone Ash," from Narracoorte, South 

 Australia, were given by Mr. N. T. M. Wilsmore (Mel- 

 bourne University). This was an account of a fossil guano 

 which might be successfully used for making cupels for silver 

 assays, &c. Other papers read were " Minerals of East Gipps- 

 land," by Mr. Donald Clark ; and " Notes on the Exudations 

 yielded by some Australian species of Pittosporum," by Mr. J. 

 Marden. A Committee was appointed to make a complete 

 census of the minerals of Tasmania for the next meeting of the 

 Association! 



SECTION C. 



GEOLOGY AND PALEONTOLOGY. 

 Prof. T. W. E. David, of Sydney University, President of 

 this Section, delivered an address on volcanic action in Eastern 

 Australia and Tasmania, with special reference to the relation 

 of volcanic activity to oscillations of the earth's crust, and to 

 heavy sedimentation. The evidences of volcanic action in past 

 geological time in East Australia and in Tasmania were re- 

 viewed historically, commencing with,the oldest known lavas — 

 the Snowy River porphyries — and concluding with the most 

 recent — those of Tower Hill, near Warrnambool, in Victoria. 

 The geological age of the former has been established as being 

 lower Devonian, whereas the occurrence of the skeleton of a 

 dingo under beds of volcanic tuff at the latter locality shows 

 that those volcanic rocks are of recent geological age. Special 

 reference was made to the vast development of contemporaneous 

 lavas and tuffs in the Upper Palzeozoic coal-fields of New South 

 Wales, at Raymond Terrace, near Maitland, and at Kiama, in 

 the Illawarra coal- field. Proofs were adduced to show that the 



lavas and tuffs at the latter locality were erupted prior to the 

 deposition of the Bulli coal-measures, as marine fossil shells of 

 Permo- Carboniferous age have been found in the volcanic tuffs 

 of that series. The great plateau of diabasic greenstone, which 

 occupies so large an area in the south-eastern portion of Tas- 

 mania, was considered by the author to be probably of later 

 origin than the Mesozoic coal-measures of Fingal, Jerusalem, 

 &c., and then the Palaeozoic coal-measures of the Mersey coal- 

 field. The greenstone forming the upper portion of Mount 

 Wellington was, in the author's opinion, of later origin than 

 the New Town coal-measures near Hobart. He considered the 

 greenstone to be a variety probably of gabbro, which bad burst 

 through the marine mudstones and overlying coal-measures in 

 the neighbourhood of Hobart in the shape of broad dykes and 

 vosses, and which had spread over the top of the measures in 

 the form of a thick broad capping. If this view were correct,, 

 there would be underneath the tiers of greenstone large areas of 

 coal-measures which might contain workable seams of coal, 

 undamaged by the overlying greenstone. A brief descriptiorv 

 having been given of the basaltic lavas of Tertiary age in 

 Australia and Tasmania, the relation of the various manifesta- 

 tions of volcanic activity to oscillations of the earth's crust and 

 to heavy sedimentation was next examined. The evidence col- 

 lected by Australian and Tasmanian geologists showed that 

 volcanic action had taken place most frequently after periods of 

 prolonged subsidence had culminated in a compensating re- 

 elevation of the land. Instances were cited to prove that in 

 many cases the subsidence which preceded volcanic outbursts 

 was directly due to the local loading of the earth's crust with 

 thick masses of sediment, the weight of which bulged the 

 earth's crust downwards, displacing in the process the lighter 

 granitic magma which is considered to immediately underlie 

 the earth's crust, and bringing the under surface of the crust in 

 proximity to the heavier basic magma. This was suggested as 

 an explanation of the fact that the products of volcanic action 

 from such areas of subsidence were usually basalts rather than 

 rhyolites or obsidians, both of which last are derived from the 

 granitic magma. 



Mr. W. J. Clunies Ross read a paper entitled " Remarks on 

 Coral Reefs." Mr. W. J. C. Ross read a paper "On the Dis- 

 covery of two Specimens of Fossil Lepidodendrons in the 

 Neighbourhood of Bathurst, New South Wales, and the 

 Inferences to be drawn fiom their Occurrence." One speci- 

 men was from the gravel of the Macquarie River, but its source 

 was tuo uncertain to be of much value. The other specimen, 

 although not actually found by the writer in situ, was received 

 by him from the finder, who was able to point out the exact 

 place from which it was obtained. This was about ten miles to 

 the east of Bathurst, in some one of a series of beds of grit and 

 quartzite forming the sides of a short valley, at the head of 

 which there was a succession of three waterfalls over hard bands 

 of quartzite, the uppermost fall being over a massive conglo- 

 merate. The grit bands contained abundant casts of Brachiopods, 

 Spirifer, and Rhynconella, and the whole series of beds was 

 coloured on the geological sketch map of the colony as Silurian. 

 The late Mr. Wilkinson, however, classed the beds as Siluro- 

 Devonian ; and a very similar series at Rydal on the Western 

 Railway Line was mapped by him as Devonian. Rydal was 

 at least sixteen miles in a straight line from the locality at which 

 the fossil was found. Near Rydal there were beds containing a 

 Lepidodendron considered by Dr. Feistmantel and Mr. Carru- 

 thers as Lepidodendron iiothitm, and to be of Devonian age. 

 Mr. R. Etheridge, Jun., however, questioned the identification 

 of the species, and seemed to think it was Lepidodendron austrah, 

 McCoy, which was generally considered to be Lower Carboni- 

 ferous. It was pointed out that the fossil now found was almo>t 

 certainly derived from the grit beds containing Devonian 

 Brachiopods, and was probably of that age. If it were taken as 

 Carboniferous, then a rearrangement of the generally received 

 geology of a large part of New South Wales would be necessary. 

 As bearing on the probable Devonian age of the fossil, attention 

 was called to the fact that in the Lower Carboniferous beds of 

 Strand, N.S.W., there were two species of Lej idodendron, viz. 

 L. Veltheiviianum arid L. Volkmanniamiin. The fossil in 

 question did not resemble either of these forms, but appeared to 

 be either Z. itotliuvi or Z. australe, and, whichever it was, it 

 was likely to be older than the Strand beds, and therefore can 

 hardly be younger than Devonian. The specimens in question 

 were exhibited, and the opinion of geologists desired on the 

 questions raised. 



NO. II66, VOL. 45] 



