THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. XXXVI. — The Origin of Serpentine, a Historical 

 and Comparative Study; by W. N. Bensox. 



I. Introduction. 



II. The recognition of the intrusive character of serpentine-masses.; 



III. The process of serpentinization. 



IV. The source of the water for serpentinization. 

 V. The formation of nephrite. 



VI. The occurrence of serpentine in volcanic rocks. 

 VII. Summary and conclusions. 



/. Introduction. 



Some years ago, the writer commenced work upon the 

 Great Serpentine Belt of New South Wales, and was 

 soon fascinated by the problem of the origin of the ser- 

 pentine. A study of the modern literature showed a 

 general agreement that such serpentine-masses were 

 originally peridotites, and have been hydrated by deep- 

 seated process, in contrast with earlier text-books which 

 explicitly referred the alteration to atmospheric weath- 

 ering. It was noted that few publications compared and 

 discussed the observations upon which the new view was 

 based, but that instead there was a definite invitation to 

 take up this study. "One might urge," wrote Merrill 

 (1899), "the necessity of closer observation regarding the 

 formation of serpentine from olivine or other anhydrous 

 magnesiari silicates. That it is through a process of 

 hydration is self-evident, but as to the conditions under 

 which it goes on, literature is strangely silent." "And," 

 added Bonney, "the subject would well repay any voung 

 geologist with sufficient leisure" (1899). Since it was 



Am. Jour. Sci. — Fourth Series, Vol. XLVI, No. 270.— December, 1918. 



