Reviews — Brief Notices. 323 



lacustrine series there is a great assemblage of fluviatile and glacial 

 drifts, ranging in age from the close of the Pliocene to recent times. 

 All the gravels and glacier detritus are gold-bearing, and most of 

 them have been worked with profit. There are two great systems 

 of lodes in the mica-schists in which gold has been worked, but 

 vein- raining has now ceased. Full particulars are, however, given 

 of the workings. Accounts are also given of silver, antimony, 

 asbestos, graphite, lignite (' coal '), and of water-supply. The 

 memoir is divided into sections dealing with the physiography, 

 general geology, economic geology, and petrography. 



The University of Durham Philosophical Society has published 

 as Memoir No. 1, ati essay " On a case of Thrust- and Crush-brecciation 

 in the Magnesian Limestone, County Durham ", by Dr. D. Woolacott, 

 F.G.S. It is illustrated with 2 plans, 20 photographs, and 4 text- 

 tigures. The substance of the essay was brought last year before 

 the British Association at Dublin, and the abstract giving the author's 

 conclusions was published in the Geological Magazine for October. 



Earth Tides. — In an article on Earth Tides {Morning Post, Feb. 23, 

 1909), it is stated that Professor Hecker, of Potsdam, has arrived at 

 the conclusion that "this apparently solid earth is subject to daily 

 oscillations analogous to the tides, rising and falling twice in every 

 twenty-four hours some twenty centimetres, or about eight inches". 

 It is further stated that independent investigations which have 

 been made in the observatory at Kimberley indicate that there is 

 a gradual rise and fall in the earth's crust of more than 8 inches 

 once daily, a movement attributed to the sun's influence, but not 

 regarded as tidal. It is also mentioned that South Africa has a tilt 

 to the east in summer and to the west in winter. 

 The Rhodesian Miner's Handbook. By F. P. Mennell, F.G.S. 

 pp. vi, 167. Bulawayo: Ellis Allen, 1909. 2nd edition. Price 5s. 



In the Geological Magazine for November, 1908, p. 519, we called 

 attention to this publication, and commended it as a sound and 

 practical guide. We are glad to find that a new edition has been 

 called for, enabling the author to bring his useful work well up to 

 date and to supplement it with further information regarding the 

 mines and mining prospects. 



Mineral Discoveries in the Norther.v Territory of South 

 Australia. — Mr. H. Y. L. Brown, Government Geologist of South 

 Australia, has issued a report on recent mineral discoveries and further 

 boring operations in the northern territory. Copper-ore has been 

 discovered in a granitic area at Mount Davis Creek, in the Pine Creek 

 District; and tin-ore and gold have also been found in new localities 

 in the same district. Information is given of the borings for gold at 

 Pine Creek and Fountain Head ; also of borings for coal at Port Keats 

 and Cape Ford, which were carried to depths of 1505 and 1506 feet. 

 No payable coal-seams were encountered ; but at Cape Ford, at 

 1050 feet, fresh water was struck and it rose to the surface, and the 

 yield at 1374 feet was 1600 gallons per hour. 



"Thk Formation of Geodes, with remarks on the Silicification of 

 Fossils," is the subject of a paper by Mr. Eay S. Bassler (Proc. U.S. 



