September 26, 1907J 



NA JURE 



559 



character are called duplex, ^ with die latter simplex. 

 •' Duplex " is dominant to " simplex.' 



A successful excursion to Charnwood Forest, under the 

 o-uidance of Mr. Bell, took place on the Saturday 

 fAugust 3), and an excellent idea of the vegetation of the 

 uncultivated portions of the forest was gained by the 

 nii;mbers of the section. 



FCONOMIC GEOLOGY iN THE UNITED 

 STATES. 



s 



TRIKIXG evidence of the work which the United 

 — States Geological Survey is carrying on for the direct 

 .idvancement of mining interests throughout the country 

 i-. afforded by a batch of eight Bulletins recently received. 

 These Bulletins cover 1562 pages, and are copiously illus- 

 trated with plates and coloured geological maps. I he 

 most valuable of the series is Bulletin No. 315, dealing 

 with contributions to economic geology in 190b, the object 

 of which is to secure prompt publication of the economic 

 results of investigations made by the survey. This 

 Bulletin deals with the metals, structural materials, and 

 other non-metals. A separate bulletin will be issued later 

 dealing with survev work on coal, lignite, and peat. In 

 investigations of ores during the year, reports are given 

 bv Mr. W. Lindgren on an interesting group of thin veins 

 carrying wolfram in Boulder County, Colorado, which now 

 constitute one of the most important sources of tungsten 

 in the countrv; bv Mr. H. S. Gale, on some new deposits 

 of the uranium and vanadium-bearing mineral carnotite 

 which occur in the upturned Dakota sandstones east of 

 the coal basins in Rio Blanco County, Colorado, deposits 

 of importance as a further possible source of radium; and 

 by Mr. G. F. Kav, on the deposits of silicate of nickel 

 near Riddles, in Oregon. Much work was done in con- 

 nection with iron ores, and reports are given on the red 

 ores of the Birmingham district, Alabama, by Mr. E. K 

 Burchard ; on the brown iron ores of the Russellville dis- 

 trict, .\labama, bv the same author; and on the grey iron 

 iires'of Talladega Counlv, Alabama, by Mr. P. S. Smith. 

 Mr A C. Spencer describes the magnetite deposits of 

 Pennsylvania, and Mr. S. H. Ball the important iron-ore 

 district at Hartville, Wyoming, and the titaniferous iron 

 ore of Iron Mountain, Wvoming. An interesting investi- 

 gation was made on glass-sands by Mr. Burchard. He 

 gives the results of chemical and physical tests, not only 

 of glass-sands now in use, but also of sands from un- 

 developed deposits which seem available for use as glass- 

 m.aking material. Prof. A. H. Purdue deals with the 

 recentlv discovered phosphate fields of Arkansas, and 

 Messrs'. F. B. Weeks and W. F. Ferrier describe a new 

 and important phosphate district at Montpelier, Idaho, in 

 the western United States. The discovery has opened up 

 a new industry in the West. 



The progress of investigations of the mineral resources 

 of Alaska in 1906 is dealt with in a separate report 

 (Bulletin No. 314). An increase of nearly 50 per cent, m 

 ihe value of the gold output of 1906 over that of the 

 previous year is the best evidence of the advancement of 

 the mining industrv in Alaska. Copper mining has under- 

 gone a rapid expansion, and other mineral deposits, such 

 as coal, marble, tin, and gypsum, have also received con- 

 siderable attention. The progress has consisted in the 

 development of the older districts rather than in dis- 

 coveries of new mineral fields. 



The Juneau gold belt, Alaska, forms the subject of a 

 separate report by Mr. A. C. Spencer (Bulletin No. 287). 

 This belt comprises the mainland strip of south-eastern 

 Alaska from Berners Bay on the north-west to Windham 

 Bav on the south-east, together with Douglas Island. The 

 ore's met with are mainly gold, though silver is usually 

 present in small amounts.' At the mines of the Treadwell 

 •group in Douglas Island, the methods of mining employed 

 represent the highest possible attainment in the successful 

 working of low-grade ores. For the last few years the 

 average value of the material passing through the mills 

 has been onlv about S.?. per ton. 



The zinc 'and lead deposits of the Upper Mississippi 

 Vallev are described in great detail in a report by Mr. 

 H. Foster Bain (Bulletin No. 294). The presence of ore 



NO. 1978, VOL. 76] 



deposits in this region was well recognised as early as 

 16S7 but the early work was restricted to lead mining 

 the zinc ores being disregarded. The rise in the price ot 

 zinc ore in 1S99 attracted attention to the district, and 

 since 1903 its development has been rapid. The author 

 gives an account of the present condition of the district 

 and a statement of ideas relating to the formation of ores. 

 The geology of the district is simple. The region is one 

 of unmetamorphosed, little disturbed, sedimentary rocks 

 of Pala30zoic age, and there are no igneous rocks nor 

 recent ones near it. The ore-bearing rock is a massive 

 dolomite. The ores, consisting of blende, smithsomte with 

 i<alena and marcasite, occur in crevices, in honeycomb 

 masses in pitches and flats, and as disseminations. Ihe 

 ore bodies are doubtless due to concentration or recon- 

 centration through the action of underground waters. 



A apoloaical reconnaissance in south-western Nevada and 

 eastern California is described by Mr. Sydney H. ball 

 (Bulletin No. 308)- Ore deposits in the area described 

 appear to be confined to the PaU-eozoic rocks, the post- 

 Jurassic granitoid rocks, and the older Tertiary rocks. 



The economic geologv of the Independence quadrangle, 

 Kansas, is described by Mr. F. C. Schrader and Mr 

 Erasmus Haworth (Bulletin No. 296), who Present the 

 substance of what is known concerning the distribution 

 occurrence, and development of petrolettm and natural gas 

 ?n the quadrangle, and note briefly the more important 

 industries growing out of these ."^t""' ''^^^^^J ,^,';. 

 F C. Clapp describes the economic geology of the Amity 

 quadrangle Eastern Washington County Pennsylvania 

 ^Bulletin No. 300). The main interest in th.s area which 

 s situated near the centre of the north end of the Pitts- 

 burg coalfield, lies in the facts that it has been the seat 

 of extensive petroleum and natural gas development and 

 that it is almost entirely underlain by at least one valuable 

 seam of bituminous coal. . , ,, c r- ';„n;van 



In the last report to be noticed Mr. E. C. Sullivan 

 discusses the interaction between minerals and water 

 solutions, with special reference to g.-'^f'"' Ph;"°?}^"J| 

 (Bulletin No. 512). -Mthough not directly the result ot 

 geological field'' work, it has an important bearing on 

 such work in that it is a chennical ■nvestigaUon of some 

 of the problems most frequently met with in the study 

 of the origin of ore deposits. Some of the changes that 

 °ake place at ordinary temperature when water solutions 

 are brought into contact with rock-forming minerals have 

 been investigated. The result has been to make . 

 apparent that chemical reaction between natural s, icates 

 and salt solutions is a very general phenomenon, taking 

 place to a decided extent immediately upon contact, and 

 that the outcome is mainly an exchange of bases in 

 chemitally equivalent quantities between solid and solu- 

 tion The metal of the dissolved salt is precipitated, and 

 an equivalent quantity of silicate is decomposed, and its 

 bases enter the solution. Salt solutions as decomposmg 

 agents are much more active than pure water, and are 

 comparable with acids in this respect. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Two courses, open free to teachers in London schools, 

 have been arranged at Bedford College for Women 

 (University of London) for the Michaelmas term; they 

 are-— dl" The Organisation of Nature-study Courses in 

 London Schools," lecturer, Miss M. R N Holmer, 

 Saturdavs, 10.30, beginning October 5 : (2) Geology for 

 Teacher's of Physical Geography, lecturer Dr. C. A. 

 Raisin, W^ednesdays, 6 p.m., beginning October 9. 



In connection with the garden produce, poultry, and 

 honey competitions of the Kent County Council and of 

 the National Potato Society at the South-Eastern Agri- 

 cultural College, Wye, Kent, on Wednesday, October 2, 

 a conference will be held, when an address will be giveii 

 by the principal, Mr. M. J. R. Dunstan, to be followed 

 by discussion. 



Six lecture^., open to the public without payment or 

 ticket on the'" Historv of Statistics and the Nature and 

 Aims 'of Modern Stati'stical Methods," will be given at 



