Reviews — Great Australian Artesian Basin. 177 



seem to be contact-deposits, and they are rather rich in sulphur and 

 phosphorus. 



This report contains detailed descriptions of a great number of 

 small occurrences of iron ores of almost every possible kind in all 

 parts of the Dominion, but most of these do not seem likely to be of 

 much importance, at any rate in the immediate future. 



An interesting and useful appendix contains a detailed description 

 of the Wabana mine in Newfoundland, now one of the largest iron- 

 mines in the world, which supplies much of the ore for the Canadian 

 furnaces. There are five beds of ironstone, from 5 to 30 feet thick, 

 intercalated in Ordovician sandstones and shales. The ore is chiefly 

 haematite, with some siderite and charaosite. The iron content is on 

 the average 53 per cent, with silica up to 10 per cent and about 0-85 

 per cent of phosphorus. The ore-reserves are very large ; a con- 

 servative estimate is 2,000,000,000 tons, and this figure may 

 eventually be much exceeded. The mines are very conveniently 

 situated for shipment of the ore, being close to the coast, where the 

 water is sufficiently deep for large ships close in shore. The loading 

 facilities are so extensive as to permit the loading of 5,000 tons of 

 ore per hour. Part of the workings extend under the sea. 



It is interesting to note that a large use has been made of 

 magnetic surveys in investigating the iron-ore deposits of Canada, as 

 this method was found to give useful results in Sweden. 



E. H. E. 



A.KTESIAN Waters of Austealia. 

 IV. — The Problem of the Great Australian Artesian Basin. By 

 A. L. DU ToiT. Journ. Proc. Eoy. Soc. N. S. Wales, vol. li, 

 p. 135, 1917. ♦ 



IN the light of his extensive experience of South African geology 

 Dr. du Toit has re-examined the whole problem of the origin of 

 the great artesian basin of Australia. Professor Gregory concluded, 

 in opposition to the views of many Australian authorities, that the 

 water was partly of magmatic origin and partly water included in 

 ancient sediments during their deposition, only a small part being of 

 modern meteoric origin ; Mr. Symmonds considered that most of the 

 ■water was juvenile in the sense of Suess. Dr. du Toit's views agree 

 in the main with those of Professor Gregory in that he regards the 

 waters as originating from three sources: (1) residual (Mesozoic), 

 (2) plutonic, (3) Tertiary. The bulk of the Mesozoic water is 

 believed to have been replaced by alkaline water derived from 

 igneous intrusions : these waters are rich in sodium carbonate. On 

 the eastern side of the basin eaiiy Pleistocene surface water drove out 

 much of the still earlier accumulation and carried salts downwards. 

 However, Dr. du Toit believes that at the present time the meteoric 

 source is of most importance in keeping up the supply, though much 

 of the older water may still remain. The notable and alarming 

 falliug-off in the yield of the wells observed of late years suggests 

 the urgent need for efficient Government control of borings in the 

 artesian area. E. H. E. 



DECADE VI. — VOL. V. — NO. IV. 12 



