Reviews — British Columbia — Lode Mining. 129 



those of his colleagues in the field seem fairly considered ; and the 

 author may be congratulated on a definite and progressive piece of 

 work which will add to the already high reputation of tlie publications 

 of the Indian Survey. The story of the difficulty of deciding oti tlie 

 age of the Napeng Beds is retold, and the final identification of Avicula 

 contoria by Kossraat, associated with Cojiocardmm, Modiolopsis, and 

 Palceoneilo, with their final reference to the Rhsetic, is of considerable 

 interest. We have noticed but few errors, but E. T. should read 

 K. B. Newton on p. 299. The plates of scenery and the maps are 

 exceedingly good, and will be of the utmost value to travellers other 

 than geological who visit what appears to be a fascinating and 

 delightful country. 



IIT. — Geological Survey of Canada. 



*' PORTIONS of Atlin District, British Columbia; with special 

 Jt reference to Lode Mining" are described by Mr. I). D. 

 Cairnes (Memoir No. 37, Department of Mines, Ottawa, 1913). 

 This mining district lies on the borders of Yukon territory in the 

 north-western part of British Columbia. In 1898 it became known 

 as a productive placer-gold catnp, but the deposits are becoming 

 slowly exhausted and more attention is now given to the lode-mining. 

 Two specimens of quartz with free gold, from the Engineer Mines, 

 are shown in a coloured plate which forms the frontispiece. The 

 minerals of economic im[)ortance (other than placer gold) that are 

 found in the Atlin district include gold-tellurium quartz veins, 

 known only at the Engineer Mines and adjoining claims on the west 

 side of Taku Arm. This is a broad water-channel which receives 

 the main drainage, whence it flows ultimately into the Yukon River 

 and Arctic Ocean. There are likewise gold-silver quartz veins, 

 cupriferous silver-gold veins, silver-lead veins, copper and antimony 

 veins ; also indications of coal. 



The particular area described in this memoir is that on the western 

 side of Taku Arm, a rugged, bleak, and inhospitable land, but by no 

 means devoid of grandeur, to judge by the many photographic views. 

 Parts of the area are 3,300 feet or more above the Taku water-level, 

 or 5,460 feet above the sea. The valleys are well wooded, and trees 

 grow 'in some sheltered places up to 2,000 feet above the valley 

 bottoms. The geological formations in this western area include the 

 Laherge Series (Jura-Cretaceous), consisting of conglomerates, sand- 

 stones, grey wackes, tuffs, shales, slates, and quartzites ; the Braebtirn 

 Xm(?.5/!o»^.9 (Carboniferous ?); and the J//f. Stevens fi^rort/* (pre-Devonian, 

 and probably Lower Palaeozoic), chiefly schistose amphibolites, 

 crushed basic volcanic rocks, mica and hornblende gneisses, sericite 

 schists, quartzites, and limestones. There are also the Chieftain Hill 

 volcanics, chiefly andesites, andesitic tuffs, and breccias (probably 

 Tertiary); and the Coast Range intrusires, eliiefly grano diorites 

 (Jurassic?). Quaternary deposits comprise gravels, sands, boulder- 

 clays, silts, ' muck,' and peat. 



The ores at the Engineer Mines occur in veins mainly in the Jura- 

 Cretaceous. Some compound veins are more than two hundred feet 



DECADE VI. — VOL. I. — NO. III. 9 



