Geology and Mineralogy. 255 



8. The Physical Geography, Geology, Mineralogy and 

 Paleontology of Essex County, Massachusetts • by John Henry 

 Sears. 1905, pp. 418, figs. 209, map in pocket. Salem, Mass. 

 (Published by the Essex Institute.) — The region described in 

 this handsome volume is both interesting and exceptionally varied 

 from the geological point of view, especially as regards its igneous 

 rocks and glacial geology. The author's intimate acquaintance 

 with the county, based on many years of residence and study, 

 renders his exposition detailed and authoritative. The numerous 

 good illustrations are mostly from photographs, the type and 

 paper irreproachable, and the publication is a valuable contribution 

 to the geology of the Eastern States and highly creditable alike 

 to its author and to the Essex Institute. h. s. w. 



9. Lead and Zinc Dep>osits of Virginia; by Thomas L. 

 Watson. Geol. Survey of Virginia, Geol. Series Bulletin, No. 1. 

 Pp. 156 with 14 plates and 27 figures, 1905. — This is an interest- 

 ing account of the important lead and zinc deposits of Virginia, 

 with a discussion on the genesis of the ores and the methods 

 employed in mining and smelting. The lead and zinc mines 

 group themselves into two divisions : (1) those of southwest Vir- 

 ginia limited to the Great Valley region and (2) those of the 

 crystalline belt, or Piedmont region, east of the Blue Ridge 

 mountains ; almost all the ore production has been from the 

 former region. The estimated annual output from the Virginia 

 mines, from 1894 to 1903, is given as not exceeding 15,000 tons ; 

 the minerals forming the bulk of this are smithsonite and cala- 

 mine. 



10. Asbestos: its Occurrence, Exploitation, and Uses / by Fritz 

 Cirkel, M.E. Pp. 169, with 19 plates. "Ottawa, 1905. Mines 

 Branch, Department of the Interior. — The asbestos industry of 

 Canada, which had its beginning in 1877, has now attained such 

 magnitude that this monograph on the subject is of particular 

 interest. The author states that there are now sixteen mills, with 

 a capacity of 3500 tons per day, in active operation and that 

 there is every prospect of this output being largely increased in 

 the course of the present year. 



Of the two mineral species included under this name, the 

 only one which has any importance in Canada and the one which 

 has proved to be much the more useful in application to the arts, 

 particularly because of its relative strength of fiber, is the fib- 

 rous variety of serpentine, called chrysotile. The fibrous variety 

 of amphibole, corresponding mostly to tremolite and in part to 

 actinolite, while mined to some extent in Italy and elsewhere, 

 and occurring in Hastings County, Ontario, has proved to be of 

 much less importance. Fibrous serpentine occurs in the Laur- 

 entian formation, in the Templeton area, north of Ottawa, in con- 

 nection with serpentinous limestone, and also in the eastern town- 

 ships in the Province of Quebec. Deposits in the former area 

 have been to some extent exploited, but without any great suc- 

 cess. The region in which active work has been carried on now 

 for nearly thirty years is that south of Quebec, including Thet- 



