REVIEWS 659 



The Nature 0} Ore Deposits. By Dr. Richard Beck. Trans- 

 lated and Revised by Walter Harvey Weed, E.M. (Engi- 

 neering and Mining Journal, 1905.) Pp. 685, 272 figures and 

 map; 2 vols. 



The arrangement of this work is based upon the method of deposit, 

 instead of grouping the descriptions under the name of the predominant 

 metal. Primary ore deposits are treated first, and are classified as " syn- 

 genetic" (formed simultaneously with the country rock) and "epigenetic" 

 (formed later than the country rock). Syngenetic deposits are divided 

 into "magmatic segregations" and "sedimentary ores." Epigenetic 

 deposits are classified as either veins or deposits other than veins, of which 

 there are four kinds. These are (a) impregnation of non-calcareous rocks 

 (deposits usually in beds); (b) epigenetic stocks, formed by metasomatic 

 replacement of calcareous rock; (c) contact metamorphic ore deposits; 

 (d) ore-bearing cavity fillings. 



Secondary deposits are classified as (i) residual deposits formed by 

 alteration of primary deposits, and (2) placer deposits. 



The subject of ore deposits is treated in an exhaustive way and exam- 

 ples are taken from all parts of the world. The translator has slightly 

 abridged the historical matter and has revised and added a little to the 

 descriptions of American ore deposits. 



E. W. S. 



Physiography of the Archean Areas of Canada. By Professor 

 A. W. G. Wilson, McGill University, Montreal, Canada. 

 (Eighth International Geographic Congress Report, pp. 116-35; 

 2 maps, 6 plates.) 

 The basis of this paper is the reports of explorers, together with some 

 of the author's own work. It is an excellent discussion of the physiography 

 of this little-known region. The geology is not taken up, but the purpose 

 of the paper is rather to draw attention to the physiographic unity of 

 the whole region. This broad Archean area is held to be an old pene- 

 plain which has been subjected to differential elevation, denudation, and 

 slight incision by the sea around the margin. It is bordered by an ancient 

 belted coastal plain. A younger coastal plain borders Hudson Bay. 

 Glacial drift covers most of the territory, and the glaciation of this pene- 

 plain of crystalline rocks has resulted in the present lakes, muskegs, and 

 other features of topography. 



E. W. S. 



