Reviews — Aquamarine Mines in Baltistan. 233 



Hence the whole coal reserves of the Netherlands, probably workable 

 under present engineering and economic conditions, amount to 

 5,256,000,000 tons, without taking into account supplies that may 

 become available at a later date. In the Buurse-Hengele district in 

 the south-east of Overijssel, the coal was found to lie too deep, but 

 important beds of rock-salt were encountered. The vast deposits of 

 salt found both here and in the Winterswijk district suggest the 

 possibility of finding both potash salts and petroleum. 



The report gives a detailed account of the stratigraphy and 

 palaeontology of the beds passed through by the borings, the palseo- 

 botany being dealt with by Dr. W. J. Jongmans. The local 

 development of the strata is carefully compared with those seen in 

 France, Belgium, and Westphalia. The Upper Carboniferous is 

 divided into four groups, respectively designated the Maurits, 

 Hendrik, Wilhelmina, and Baarlo stages, in descending order. Each 

 of these appears to be characterized by a special assemblage of fossil 

 plants. 



The whole investigation affords an admirable example of far-seeing 

 and well-directed enterprise, and both the Government and the staff 

 employed are to be congratulated on the results obtained, which seem 

 likely to lead to important commercial developments in the near 

 future, possibly rendering Holland economically independent of 

 foreign supplies of coal. The sufferings of the country in the last 

 four years will doubtless stimulate efforts in this direction in view of 

 a possible repetition of such conditions in the event of a future war. 

 E. H. E. 



Y. — Note on the Aquamarine Mines oe Daso, Baltistan. By 

 C. S. Middlemtss and L. G. Paeshad. Bee. Geol. Surv. India, 

 vol. xlix, pt. iii, pp. 161-172, with 5 plates, 1918. 



IK 1915 an important deposit of aquamarine was located at Daso, 

 on the Braldu Biver, Shigar Valley, Baltistan, Kashmir, and it 

 is now being actively exploited. The country rock for miles round 

 is biotite-gneiss with big veins of coarse pegmatite, consisting of 

 quartz, orthoclase with some albite, tourmaline, muscovite, garnet 

 and beryl. The best and most transparent beryls are found in drusy 

 cavities, and the prisms are often np to 3 inches long, while crystals 

 of opaque varieties may be as much as 6 inches in length. The 

 colour of the best specimens is not very deep, but of the true 

 aquamarine shade. The available supply appears to be very large, 

 but mining is somewhat handicapped by high transport charges for 

 stores and equipment. 



VI. — Obseevaciones Geologicas en la Isla de Gomera (Canaeias). 



By L. F. Navarro. Trab. Mus. Nac. Cien. Nat., Geological 



Series No. 23, pp. 87, with 34 text-figures and a map. 



Madrid, 1918. 



rriHE author has paid several visits to this little-known island, of 



JL which he describes the topography and geology in some detail. The 



island is remarkable for the abruptness of its shores and the general 



steepness in its slopes. It is deeply dissected by a large number of 



