RECENT ADVANCES IN SCIENCE 3S3 



sufficient pressure and heat to recrystallise a large part of 

 the formation. 



The unique seam of iron pyrites occurring at Trefriw 

 (Carnarvonshire) is 6 feet thick, and separates an intrusion 

 of dolerite from black shales of Dicranograptus age (R. L. 

 Sherlock, Q.J.G.S. 1919, 74, pt. 2, 106-15). It lies at the 

 horizon of certain pisolitic iron ores in North Wales. The 

 pyrites is believed to have originated by the action of heated 

 magmatic waters, derived from the dolerite magma, upon the 

 iron ore. 



For the pyritic deposits of Roros, Norway, Ries and Somers 

 (Amcr. Inst. Min. Eng., 191 8, 58, 244-64) favour the view that 

 these are due to magmatic injection into the enclosing schists. 

 In support of this hypothesis they point to the absence of 

 hydrothermal alteration in the wall rocks ; the uniformly close 

 association of the ore with gabbro ; the presence of unori- 

 entated inclusions of wall rock in the ore ; and the nature of 

 the ore itself, which is massive, occasionally porphyritic, and 

 not always conformable to the enclosing schists. 



In a paper on geosynclines and petroliferous deposits, 

 M. R. Daly {Trans. Amer. Inst. Min. Eng., 191 8, 57, 1054-70) 

 shows that the latter follow the main zones of dislocation upon 

 the globe. " Petroliferous accumulations are generally coin- 

 cident with diastrophic deformation, synchronous with them, 

 and essentially a result of them." 



Garfias and Hawley describe funnel and anticlinal ring 

 structure associated with igneous intrusions in the Mexican 

 oil-field (Trans. Amer. Inst. Min. Eng., 1918, 57, 1071-88). By 

 these terms is meant the dragging down of strata around the 

 periphery of a volcanic vent, producing an anticlinal ring sur- 

 rounding the volcanic funnel. This is the familiar structure 

 seen in many vents of the Midland Valley of Scotland, as noted 

 by the authors. In the Mexican oil-field these structures have 

 been found to be ideal for the accumulation of oil. 



Prof. P. G. H. Boswell has followed up his well-known 

 work on glass sands by an equally useful memoir on refractory 

 sands for furnace and foundry purposes in A Memoir on 

 British Resources of Refractory Sands for Furnace and Foundry 

 Purposes, pt. 1 (published at the instructions of the Ministry 

 of Munitions of War, by the Imperial College of Science and 

 Technology and the University of Liverpool. London : 191 8, 

 pp. 246). This contains by far the fullest discussion of the 

 characters of moulding sands that has yet appeared. A novel 

 point is the insistence upon the value of the pellicle of ferric 

 oxide around the grains of the red Bunter moulding sands as 

 a medium for the retention of water, thus strengthening the 

 bond " of the sand. The concise chapter describing the 



