444 



NA TURE 



[Febkuaky io, 1910 



The Annual Report of the Geological Survey of Western 

 Australia for 1908 (Perth, 1909) contains an account of 

 the phosphatic deposits of Christmas Island, by Mr. H. P. 

 Woodward. The travertine that has become phospha- 

 tised from above is about 2 feet thick, and is ascribed to 

 the evaporation of capillary waters, which bring calcium 

 carbonate in solution from underlying shelly sands. This 

 kind of rock may be matched in South Africa and in other 

 countries where rains are only seasonal. The fundamental 

 rocks appear along the coast and in bold hills at the north 

 and south ends of the island. They are granite, gneiss, 

 and schist, with basic dykes rich in magnetite. A large 

 number of analyses of the phosphatic beds and a map of 

 the island are supplied. The Survey has reprinted three 

 earlier bulletins on the Pilbara goldfield in a compact 

 little volume (1908), with a large number of folding maps 

 and plans. This goldfield is in a tropical region east of 

 the Yule River. The gold occurs in quartz-reefs, mainly 

 in a green schist series, which is probably of igneous 

 origin. Alluvial tin-ore is also worked, and has been 



(p. 10) ; bands of laterite, moreover, traverse the country 

 like lodes, but are believed to be only the weathered tops, 

 of basic igneous dykes (p. 12). Certain andalusite-sericile 

 schists are attributed to the alterai'on of granites rich in 

 soda and alumina (pp. 21 and 23J. The coloured map of 

 Ravensthorpe is impressive, with its grand series of basic 

 dykes running across the granite from a greenstone region 

 in the north-west. These dykes can usually be recognised 

 across country by the rich red soil upon them. Bulletin 

 No. 37 (igog), by Mr. C. G. Gibson, is of imperial import- 

 ance, being a description of the geology along the proposed 

 transcontinental line of railway through Australia from 

 west to east, so far as the route lies in the State of 

 Western .A.ustralia. The illustrations of camels procuring 

 water at small holes in bush and desert are not encouraging 

 to the townsman, but will probabl}' serve only as a stimulus 

 in these lands of healthy enterprise. These remarkably 

 cheap reports, in which maps and memoirs are combined, 

 must be of immense service in a country intent on under- 

 standing its resources. 



Fig. 2.— Mount Lambert, New Zealand Alpi 



traced to local granite masses. Bulletin No. 32 (1908, 

 price 2S.) is also a guide to miners in special districts. 

 The tests given for the ready discrimination of ores are 

 an excellent feature, and that on p. 12, for cassiterite in 

 a concentrate of similar heavy minerals, is new and 

 fascinating. Native tin has been found (p. 22) in the 

 Greenbushes tinlield in the south-west of the State, and is 

 rtttributed to the action of bush-fires on surface ores. 

 Tanlalite is of growing importance in .Australian fields. 

 Mr. Gibb Maitland pointed out some years ago that the 

 laterite of the Greenbushes area is being denuded away. 

 Mr. H. V. .Woodward now states (p. 31) that the deposit 

 appears in places as a zone between two alluviums. It 

 has resulted from the alteration of rocks as diverse as 

 diabasic schist and alluvium, under conditions of climate 

 that may have been recurrent, but which do not now 

 pre%'ail. Bulletin No. 35 (1909) deals with the gold and 

 copper deposits of the Phillips River Goldfield, about 150 

 miles east of Albany. The basic schists of the region are 

 capped by latefite and the serpentines by magnesite 

 KO. 2102, VOL. 82] 



The Secretary for Mines for South Australia issues a 

 review of mining operations in the State for 1908 (Adelaide, 

 1C09). Mr. H. Brown describes certain phosphate deposits 

 (p. 21), which have a general interest because of their 

 irterstratification with Cambrian clays, sandstones, and 

 limestones. It' is suggested, as in the case of the Welsh 

 beds, that the calcium phosphate results from the abund- 

 ance of organisms which utilised it in their shells in 

 Palaeozoic times. .At present these deposits are over- 

 shadowed commercially by Christmas and Ocean Islands. 



The Geological Survey of New South Wales issues a 

 report and map, by Mr. E. C. -Andrews, on the Drake 

 Gold and Copper f'ield, where folding at the close of 

 Carboniferous times was accompanied by successive 

 intrusions of granitic magmas of decreasing basicity. 

 Dioritic dykes then broke through, with which the gold, 

 copper, lead, and silver ores are associated. The mineral 

 features are thus of early Mespzoic age (p. 6).. The 

 porphyritic hornblende-granite of Malarra (p. 9), a member 

 of the earlier intrusions, seems of unusual attraction 



