116 



GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS, 



considerable beds of white crystalline limestone, dolomite, and tremolite 

 schist, and in the liu-ther prolongation of the bed across Russell and "West- 

 field the enstatite-serpentines and the half-altered beds of very coarse 

 enstatite rock associated with great beds of crystalline limestone become 

 entirely predominant. The black, fissile amphibolites accompany the ensta- 

 tite-serpentine beds to the end. 



The presence of dolomite as an original constituent, both as inclusions 

 in the unchanged enstatite and in the interstices of the enstatite rock, as 

 well as in great beds, indicates the derivation of the whole series from large 

 beds of dolomitic limestone. The subject is summarized on page 147, after 

 the description of the emery bed. 



Below is given a table of all the analyses of serpentines known to me 

 from this area. The material used in the analyses 1 to 6 was furnished by 

 the author, and, excepting 2 and 9, great care was taken to detect all the 

 rarer constituents, especially nickel, cobalt, and chromium. 



Analyses of serpentines. 



[Nos. 1, 3, 5, 6, and 8, by Mr. George Steiger, in the laboratory of the United States Geological Survey ; No. 3, by Miss 

 H. P. Cook, instructor in chemistry in Smith College ; No. 9, by Prof. 0. U. Shepard ; No. 2, by Melville, quoted from Bana's 

 Manual, p. 672; Nos. 4,7, and 11, by Dr. W. F. Hillebrand, of the United States Geological Survey.] 



No. 1. Rich, dark-green serpentine. Howe. Qn 

 No. 2. Picrolite. Florida. 



No. 3. Straw-yellow, fibrous aerpeotine, glazed, 

 men figured in Bull. U. S. Geol. Survey No. 126. PI. I. 



nveloping olivine pseudomorphs. Middlefield. From the speci- 



