Brief Notices. 41 



of the minerals produced during the period with that of the previous 

 five years, an increase in value is noted in every case except rubies. 

 The average increase, which amounts to more than 2\ million pounds, 

 is due mainly to progress in developing coal, petroleum, salt, gold, 

 manganese-ore, and mica. Attention has been given also to the 

 development of bauxite, copper-ore, and lead-silver ores. 



7. Rivers. — In a paper brought before the Cotteswold Naturalists' 

 Club, but regarded as too controversial for publication in the 

 Proceedings, and now issued separately (Gloucester, 1910, price Is.), 

 Mr. T. S. Ellis has dealt with ' ' The Winding Course of the River Wye ". 

 Believing that an area uplifted from the sea would have an irregular 

 surface and that the streams would form a network, some meeting 

 again after being diverted, some branching off to unite with other 

 streams, he rejects the idea of primary consequent streams — we 

 presume in the sense of their having an entirely independent origin. 

 His observations lead him to conclude that the Upper Wye formerly 

 continued its course through the Talgarth Yalley to the Usk, and that 

 tidal influence played an important part in forming the course of the 

 river during the gradual elevation of the land. 



8. River Action. — Mr. F. M. Burton, author of The Shaping of 

 Lindsey by the Trent (1907), has issued another little work entitled 

 The Witham and the Ancaster ' Gap ' : a Study of River Action 

 (1910). In this the formation of the Ancaster Gap is attributed 

 to a former course of the River Devon, which now flows into the 

 Trent west of Newark. The possible influence of the ice of the 

 Glacial Period in impounding the drainage and causing the erosion 

 of the gap, as advocated by Mr. Planner, is not discussed. 



9. Geological Map of Cape Colony. — We have received two sheets 

 of the colour-printed Geological Survey map on the scale of 3f miles 

 to 1 inch, by Dr. A. W. Rogers and Mr. A. L. Du Toit. Sheet 

 No. 40 includes the country around Marydale, traversed by the Orange 

 River ; and Sheet 32, which adjoins on the south, takes in the country 

 around Van Wyk's Ylei. In the northern area the quartzites of the 

 Kheis Series and large tracts of granite that intrude into them, 

 dominate the country ; in the southern area the Karroo System with 

 dolerite intrusions extends over the greater part. Longitudinal 

 geological sections are printed on the margins of the maps. 



10. Geological Survey of Western Australia. — Bulletin No. 33 

 (1909) contains the results of "Geological Investigations in the 

 Gascoyne, Ashburton, and West Pilbara Goldfields", by Mr. A. Gibb 

 Maitland, Government Geologist, with Petrological Notes by Mr. J. 

 Allan Thomson. It is well illustrated by 13 geological maps and 

 65 figures, comprising plans, sections, and pictorial views. The 

 mineral resources, in addition to gold, include stream-tin, lead and 

 copper ores, and mica. Artesian wells in the Gascoyne district 

 yield more than eleven million gallons of water daily from seventeen 

 bore-holes that range from 850 to 3,011 feet in depth. The rocks 

 described by Mr. Thomson include schists, quartzites, cherty 

 carbonates, marble, dolomites, serpentine, gabbro, amphibolite, 

 dolerite, and granite. 



