306 Scientific Intelligence. 



facilities for carrying on the various lines of experimental work, 

 both physical and chemical, in testing fuels, explosives, etc. The 

 publications of the Bureau include an extended series of bulletins, 

 also a number of technical papers and finally a series of miners' 

 circulars. 



2. Tlie Platinum and Platiniferous deposits of the Ural. — 

 Prof. L. Duparc has given (Arch. Sci. phys. nat., vol.xxxi) a full 

 and valuable account of the deposits of platinum in the Ural, the 

 single region upon which the world depends now foV substantially 

 all its supply of that metal. His researches on the subject have 

 extended over a period of more than ten years. Briefly stated, 

 he shows that the platinum is immediately associated with a band 

 of basic eruptive rocks following more or less closely the water- 

 shed between Europe and Asia, particularly on the eastern side 

 of the mountains. This band extends from the northern to the 

 central Ural, while farther south it is continued by a series of 

 isolated occurrences having the same general trend. In this, the 

 western, zone occur the important deposits of platiniferous dunite. 

 To the east lies a second band, shorter and not continuous, in 

 which serpentine i*beks prevail; just to the south of Ekaterinen- 

 burg it disappears or becomes lost in the first zone. These bands 

 are flanked on both sides by metamorphic crystalline schists. 



With respect to the individual occurrences, described in detail 

 by the author, they show in general a mass of dunite at the 

 center, more or less elliptical in form, with its axis approximately 

 north and south. A border of more or less developed pyrox- 

 enite — also carrying platinum — is observed accompanied by 

 certain melanocratic rocks and, in addition, an external zone of 

 feldspathic rocks, including gabbros, diorites, etc. 



The platinum occurs in the dunite both directly crystallized with 

 the olivine and also with the chromic iron ; in the latter case the 

 platinum sometimes forms a spongy mass enclosing chromite 

 grains. Both in the dunite and the pyroxenite the platinum is 

 regarded as a magmatic mineral, a product of the differentiation 

 of the magma. It is interesting to note that by careful search it 

 has been found possible to observe the platinum in place in the 

 dunite, although such an occurrence is rare. 



The author has also earlier described (with P. Pamphil) the 

 various peculiar types of rock associated with the platinum 

 (koswite, issite, etc.) and has also (with H. C. Holtz) given anal- 

 yses of many samples of the platinum. 



3. The Gabbros and Associated Rocks at Preston, Connecti- 

 cut ; by G. F. Loughlin, Bull. 492, U. S. Geol. Surv., 1912. — 

 This bulletin describes an area of about one hundred square miles 

 in eastern Connecticut. The bed rock formations comprise (1) 

 Metamorphic sedimentary rocks — quartzite, quartz-biotite schist, 

 hornblende schist, black pseudoporphyritic schist (Kinsigite), and 

 dolomite ; these are assigned provisionally to Cambrian and Car- 

 boniferous ages. (2) Gabbro — two principal and several minor 

 varieties. (3) Granite — three varieties. The gabbro was the 



