January 27, 1910] 



NA TURE 



381 



price 4s.). accompanies the colour-printed map, Sheet 347 

 (price IS. 6d.). The tin and copper mines are described, 

 with sections. Considerable interest attaches to the origin 

 of china-stone and china-clay (p. 105) ; the former is an 

 altered granite, in which kaolinisation is not an essential 

 feature. It must not contain tourmaline, or minerals liable 

 to discolour it. China-clay, on the other hand, must be 

 a kaolinised product, and tourmaline can be washed out 

 of it during its preparation for commercial use. Mr. 

 Mac.Alister (p. 115) attributes the main kaolinisation to 

 " moisture with fluorides emanating from the granite," 

 while Dr. Flett (p. 118) believes in the greater potency of 

 carbonic acid. Hence we are by no means at the end of 

 this much-discussed question. The metamorphism of the 

 Devonian rocks by a granite associated with the Hercynian 

 folding furnishes interesting material. We wish that Mr. 

 Barrow could have been restrained from promulgating the 

 .\ngIo-Swedish word " calc-flinta " (p. 99), which can 

 hardly be taken as a serious term. It appears, however, 

 on the index to the map, where it has become classed, 

 with associated altered sediments, as of igneous origin. 



The Scottish branch of the Survey recalls the ancient 

 state of things, when romance and argument by flood and 

 field were to be sought northward of the Tyne. The 

 memoir on Shegt 45, including Oban and Dalmally (1908, 

 price 2S, 6d.), has for its frontispiece the Pass of Brander, 

 through which the Atlantic always seems to call, 

 across the rain-swept moorland under Cruachan. Mr. H. 

 Kynaston, before his departure for the Transvaal, surveyed 

 this region with Mr. J. B. Hill, and several other authors 

 have joined in the present memoir. Much of the interest 

 of the area is petrographical, but nowhere is the petro- 

 grapher more dependent on the relations of the rocks as 

 determined in the field. Take, for instance, the marginal 

 features of the Cruachan granite (p. 83), or the pitchstone 

 with cordierite, augite, magnetite, and spinel (p. 129), which 

 results from the fusion of a phyllite by a Cainozoic dyke. 

 Bibliographers should be warned that one of the authors 

 nf this memoir, Mr. H. B. Muff, changes his name hence- 

 forward to the ancestral form of Maufe. Under this guise 

 he appears as joint author with his colleagues, Messrs. 

 Clough and Bailey, of a very striking paper on the 

 Cruachan and GJen Coe cauldron-subsidence, in the 

 Quarterly Journal of the Geological Society for November, 

 TQOQ. It is not too much to say that the researches of the 

 Geological Survey have added to our appreciation of one 

 of the grandest regions of the Highlands. 



The memoir on Sheet 36, covering the seaboard of Mid- 

 Argvll, is mainly bv Mossrs. Peach, Kynaston, and Muff 

 (igog, price 2s. ^d.). Effective illustrations are given of 

 the remarkable boulder-beds traceable above the limestone- 

 zone of the metamorphic series. The reality of the break 

 marked by this conglomerate is shown by its frequent 

 inclusion of local rocks, such as the limestone blocks in 

 the Garvellachs. Rocks from unknown sources also occur. 

 The chapter (p. 43) on the epidiorites of the area, and on 

 their origin as " pillowy " basic lavas, will be of value 

 to geologists in many countries who have to deal with 

 this group of modified rocks, in which a similarity of 

 character has been thrust on materials of very various 

 modes of upbringing. The slate quarries of Easdale have 

 been studied in their economic aspect, and Mr. Muff con- 

 tributes (p. 16) a valuable exposition of the relations of 

 the various parting-planes to the folding of the rocks, 

 which is applicable to many other cases difficult of inter- 

 pretation, even in the field. 



The Records of the Geological Survey of India contain 

 evidence of a great variety of observations, ranging from 

 economic materials to fossil remains. In the mineral 

 field Dr. Bleeck deals with jadeite, which is extensively 

 worked in a dyke or in detrital boulders by Chinese 

 enterprise in Upper Burma (vol. sxxvi., p. 254). He 

 concludes that pure jadeite consists of the (metasilicate) 

 NaAlSi.O,, and that the dyke in the Kachin Hills origin- 

 .•dly consisted of nepheline, NaAlSiO,, and alhite, 

 Xa.MSi.O.. One molecule of each of these would produce 

 naragenetically two molecules of jadeite. Albite occurs in 

 both margins of the dvke, as is shown in the interesting 

 section en p. 276, and these marginal zones contain blocks 

 picked off from an adjacent amphibolite. It is presumed 

 that the original magma was unusually rich in soda. Mr. 



NO. 2100, VOL. 82] 



Fermor (vol. xxxvi., p. 295) verifies by new analyses the 

 view of Laspeyres, that psilomelane is a definite man- 

 ganate of ma'nganese, barium, iron, potassium, and 

 hydrogen, based on the acid H.MnOs. Hollandite is 

 crystallised psilomelane, while coronadite of Arizona is 

 held to be a form in which barium is replaced by lead. 

 Mr. P. N. Bose's account of the mineral resources of 

 Rajipld (vol. xxxvii., p. 167) describes the carnelian mines 

 of Ratanpur, which have been worked for 400 years. The 

 stones are coloured by heating on the spot. The date of 

 Mr. Copland's report is not given, but we judge it tobe 

 about 1830. At that time the miners walked seven miles 

 to the mines and seven miles back every day, " on account 

 of the tigers with which the country abounds." In the 

 same volume (p. 199! Mr. Fermor describes three new 

 manganese minerals from India, vredenburgite, probably 

 3Mn3 0^.2Fe,03, and highly magnetic ; sitapdrite, 

 9Mn,0,.4Fe;03.Mn0,.3Ca0, with a bronzy colour dis- 

 tinguishing "it from 'braunite ; and juddite, a manganese 

 amphibole. Specimens of all these may now be seen in 

 the British Museum collections. 



In phvsical geology we note Mr. J. C. Brown's descrip- 

 tion of ' the mud-volcanoes of the .Arakan coast, Burma 

 (vol. xxxvii., 1909, p. 264), which are produced by the 

 bursting up of petroleum vapours, and which occasionally 

 build up temporary islands in the sea. Sir T. H. Holland 

 and Mr. W. Christie furnish an important paper on the 

 origin of the salt-deposits of Rajputana (vol. xxxviii., 

 1909, p. 154). They show, in the first place, that the 

 rivers flowing into the basins in which the salt accumu- 

 lates in dry seasons contain an unusual amount of sodium 

 chloride : secondly, that this is not likely to be washed 

 out of older salt-beds : and thirdly, by actual experiments 

 at Pachbadra, that the amount of salt passing a front 

 300 km. broad and 100 m. high during the four hot- 

 weather months is some 130,000 tons. Mr. T. D. 

 La Touche suggested in 1902 that the salt in the great 

 plains might be added to by wind-borne drift, but the 

 present writers conclude that this is the essential method 

 of supply. The Rann of Cutch becomes actually crusted 

 over with salt in the dry season ; magnesium^ and 

 potassium salts, being more soluble, are left behind in the 

 unevaporated water (p. 168), and the sodium chloride, prob- 

 ably with gypsum, is carried inland. Small Foraminifera 

 have been blown inland from the Cutch coast for 500 miles. 

 The rains follow on the hot months, and the salt is 

 washed into temporary lakes before it can be blown back 

 bv the return monsoon. The application of this striking 

 instance to the Triassic lake-basins, formed under desert 

 conditions (p. 183), makes it of wide importance, _ Judg- 

 ing from the immense stretches of oebble-beds in the 

 European Trias, and from the signs of extension and re- 

 cession of the lakes, flood-w.aters arising under monsoon 

 influences may have prevailed in a region that was dry 

 during a large part of the year. Gypsum beds like those 

 of our Trias are found deposited from the seasonal lakes 

 of north-west India. . ^ 



Stratigraphy is represented by Mr. G. E. Pilgrim s 

 investigation of Tertiary fresh-water deposits in Baluchistan 

 and Sind (vol. xxxvii., p. 139), in which he divides up beds 

 previously grouped as Siwalik into an Oligocene series 

 with An'thr'acotherium and the allied Brachyodus, an 

 L'pper Miocene series with Deinotherium and Tetrabelodon, 

 and an unfossiliferous series, which is probably Upper 

 Pliocene. Unconformities occur between these series. 

 Mr. C. S. Middlemiss, writing on the Gondwanas of 

 Kashmir (vol. xxxvii., p. 286I. suggests a re-arrangement 

 of beds previously studied. He has found a new Lower 

 Carboniferous horizon in the Lidar valley (p. 3iq), lower 

 than the Panjal volcanic series. Above the Panjal series 

 on the Golabgarh Pass he traces a section where Lower 

 Gondwana plants (Gangamopteris, Glossopteris, &c.) lie 

 beneath marine beds with a Middle Carboniferous fauna. 

 This establishes (p. 296) the position of the Lower 

 Gondwana beds in peninsular India, including the Talchir 

 glacial series. No signs of glacial conditions, however, 

 were observed in their representatives in the north. Mr. 

 E. W. Vredenburg, in a paper on a hippurite-limestone in 

 Seistan (vol. xxxviii., p. iSql, points out that Seistan 

 occupies a tectonic depression, the floor of which has been 

 covered by the lacustrine Pliocene Gobi formation, the 



