90 Reviews— Geological Survey of Canada. 
236 pages it will only be possible to bestow a mere glance upon it. 
The report begins with a history of the development of mining in the 
Sudbury district, and then goes on to describe its general physical 
features and geology. The rocks of the district are, in ascending 
order, as follows :— : 
1. Lower Huronian. No rocks of this age are at present known 
in the nickel-bearing area, but this period is represented in part by 
the banded siliceous magnetites and associated rocks of Hutton and 
‘Wissner. 
2. Upper Huronian. (a) Diorites, hornblende - porphyrites, and 
green schists; (6) conglomerates, greywackes, and quartzites ; 
(¢) norite and diorite (Worthington mine belt and areas south-east 
of Evans mine and east of Sudbury). 
3. Laurentian. Granite and diorite-gneiss near Wanapitei station. 
4. Upper Huronian? ‘Tuffs, felspathic sandstones, and slates 
classified provisionally on previous geological maps as of Cambrian age. 
5. Post-Huronian. (a) Granites; (6) nickel-bearing eruptive of 
the main belt (quartz-hypersthene-gabbro or norite, diorite, with their 
peculiar differentiation product, micropegmatite); (c) dykes of 
olivine-diabase. 
6. Pleistocene. Clays and sands. 
The granites referred to in the list (5, @) are pronounced to be 
undoubtedly younger in relation to the older diorites, porphyries, and 
green schists, and a rock which may be called a breccia, formed by an 
exceedingly intricate intrusion of dykes and masses of granitic material 
through these basic rocks, covers considerable areas throughout the 
district. 
The nickel-bearing eruptive (5, 6) is said to be decidedly later than, 
and intrusive through, the green schists and associated diorites (2, a). 
The olivine-diabase dykes (5, ¢) cut through, and are therefore later 
than, all the rocks with which they have been seen to be in contact. 
A description is given of the minerals associated with the nickel 
and copper of the Sudbury region, followed by an account of the 
methods of mining, metallurgy, and smelting. The nickel deposits of 
the United States, Scandinavia, and New Caledonia are also described 
at some length. 
The report concludes with a series of statistical tables of the 
production of nickel in Canada, which is the largest producer in the 
world; other countries being added for comparison. 
This important memoir is well illustrated with plates, maps, and 
plans. 
Mr. Henry 8. Poole reports briefly on the Pictou Coalfield of Nova 
‘Scotia. This famous coalfield has long been known to geologists 
through the writings of Gesner, Dawson, Lyell, and Logan. The 
present report has been written to accompany a revised map of this 
coalfield and its neighbourhood lately published. The district’ 
contains in a small area a wide field for investigation, supplying 
representative series of several geological epochs and many highly 
mstructive exposures of varied structure. 
The geological systems represented are as follows, in ascending 
order :— 
