REVIEWS 103 



states, Pennsylvania and Vermont being treated in considerable detail. 

 Part III takes up the problems of slate prospecting, quarrying, and the 

 uses of slate. 



Statistics for 19 13 give the total value of slate production in the 

 United States as $6,175,476. Pennsylvania produced more than one- 

 half of the total, and Vermont more than one-fourth. 



W. B. W. 



Mineral Resources of Alaska. By A. H. Brooks and Others. 

 U.S. Geol. Survey, Bull. No. 592. Pp. 413, figs. 13, pis. 17, 

 map 1. 



This bulletin is the tenth annual report upon mining conditions and 

 mineral resources of Alaska. In addition to the administrative report 

 there are given results of investigations in a score of districts during the 

 1913 field season. Several of these record the progress made in well- 

 known mining camps, while others are results of reconnaissance trips in 

 little-prospected districts. The more important of these preliminary 

 reports will be embodied in separate bulletins. In these papers emphasis 

 is laid on conclusions having immediate interest to the miner to whom 

 a prompt publication is more valuable than a detailed report long 

 delayed. 



Gold continues to be Alaska's chief source of mineral wealth. The 

 total production in 1913 was $15,600,000, of which 31 per cent came 

 from lode mines and the balance from placers. The amount produced 

 has declined rather steadily since 1906. A marked falling off in 19 13 is 

 attributed in part to unusual scarcity of water during the sluicing season. 

 The average value recovered from placers has declined from $3 . 74 per 

 cubic yard in 1908 to $1.57 in 1913. 



Coal is the only mineral product that does not show a decreased out- 

 put since 191 2, and its production is of little consequence commercially. 

 In connection with coal the author states: "As a rule, the quality of coal 

 bears a direct ratio to the amount of deformation, lignite being in least- 

 folded rocks and anthracite in those most folded." 



W. B. W. 



Mineral Production of Canada, for 1913. By John McLeish. 



Canada Dept. of Mines. Ottawa, 1914. Pp. 316. 



The value of mineral products for the year amounted to more than 



$145,000,000, of which over $66,000,000 was in metals. Coal amounted 



to over $37,000,000. The remainder is distributed over a large number 



