600 



NOTES ON SERPENTTNOUS ROCKS MERRILL. 



of the mineral. The method of alteration corresponds closely to that 

 described by L. P. Gratacap as having taken place in the amphibolic 

 rocks lying between Fifty-fifth and Sixtieth street, New York city.* 



An analysis of the tremolite, separated out from the fresh pulverized 

 rock (70122), yielded Mr. Eakius as follows: 



As above noted, the pure compact serpentine occurs only in veins 

 associated with snow-white calcite. The main mass of the rock is of a 

 dull greenish hue and consists of a mixture of serpentine, secondary 

 calcite, vermiculite, and remnant shreds of tremolite. 



National Museum, June, 1889. 



*Arn. Jour. Sci.. 3. xxxm, 1887, p. 374. 



