Reviews — Canada. 375 



lY. — Diamonds in Ekitish Columbia.' 



HITHERTO the only recorded occurrence of diamonds in their 

 original matrix in North America has been that of Pike County, 

 Arkansas, where they occurred in a peridotite. These were discovered 

 in 1908, and during the following year 700 commercial diamonds were 

 obtained. Considerable scientific interest therefore attaches to the 

 discovery, by Mr. R. A. A. Johnston, mineralogist to the Canadian 

 Surve}-, of small diamonds in chromite segregations in the peridotite of 

 Olivine Mountain in the Tulameen district. The peridotite of Tulameen 

 shows on analysis close similarity with the diamond-bearing peridotite 

 of Arkansas, and both are closely related to the ' kimberlite ' of South 

 Africa. The diamonds occur as small octahedra associated with the 

 chromite, towards which they are idioraorphic ; and as small spherical 

 patches of a yellowish colour, apparently consisting of aggregates of 

 small particles occurring in veinlets in the cliromite. The largest 

 individuals obtained are described as about the size of an ordinary 

 pin's head, but in many cases these individuals break up into small 

 particles within a few hours of being freed from their matrix. 

 Hitherto no diamonds have been found iu the gold-placers of the 

 district. It appears clear that the chromite which always accompanies 

 the diamonds is an original constituent, and crystallized later 

 than the octahedral diamonds. The peridotite is intrusive through 

 a series of rocks containing little or no carbonaceous matter, so that 

 it is probable that the carbon existed as an original constituent of 

 the magma. 



Y. — Canada. 



DEPARTMENT of Mines. From the Mines Branch we have 

 received : the Annual Report on the Mineral Production of 

 Canada for 1912, Preliminary Report on the Mineral Production of 

 Canada for 1913 and a paper on the "Preparation of ^letallic 

 Cobalt by the Reduction of the Oxide", by H. T. Kalmus and others 

 (1913). The latter publication forms part i of the researches on 

 cobalt and cobalt alloys conducted at Queen's University, Kingston, 

 Ontai'io, for the Mines Branch. 



From the Geological Survey Branch we have Memoirs 23, 25, 26, 

 30, 37, and 44, with the accompanying maps. 



Memoir 23. Geology of the Coast and Islands between the Strait of 

 Georgia and Queen Charlotte Sound, British Columbia. By J". A. 

 Bancroft, pp. 146, with 6 figures in the text, 17 plates, and 1 map. 

 1913. — Although this is to be regarded as a preliminary report, it 

 contains much material of great scientific interest. Those interested 

 in physical geology will find many valuable observations on fiords 

 and hanging-valleys, with a discussion of their origin. The petro- 

 graphy of the igneous rocks of the Coast Range and of the regional 

 and contact metamorphism of the stratified rocks is treated in detail. 

 The plutonic rocks occur in the form of large batholiths. These 

 have been dissected to considerable depths by the fiords, and the 



^ Geology and Mineral Dex>osits of the Tulameen District, British Columbia. 

 By Charles Camsell. Canada, Department of Mines, Geological Survey, 

 Memoir No. 26, pp. 146-53. 



