5io 



B. K. EMERSON 



Si0 8 ... 

 Al s O s . 

 Fe 2 (J 3 .. 

 FeU . . . 

 MgO... 

 CaU. . . 

 Na s O.. 

 K a O.:. 

 H 2 — 

 H 2 + 

 TiO s . . 

 ZrQ 2 .. 



CO,... 



p 2 o 5 .. 



s 



MnO... 

 BaO... 

 SrO.... 



Li s O .. 

 CuCu. . 



J 7 2 



a little lost 



none 



none 



none 



•I4 2 



99-77 



60.13 

 20.47 

 1 .04 

 .72 

 1. 15 

 2-59 

 9.60 

 1.06 



trace 



3-44 

 (Ignition, 

 includes H 2 0) 



trace 



III. 



51-78 

 12.79 



3-59 

 8.25 



7-63 



10.70 



2. 14 



0-39 



•63 



1. 41 



■14 

 0.44 



99.89 



I. Analysis of Holyokeite made by Mr. Hillebrand, of the United States Geo- 

 logical Survey. 



II. Analysis by Dr. H. S.Washington of the acid dyke in the Connecticut Trias, 

 described by Mr. E. O. Hovey and mentioned below. Specific Gravity at 1 1 ° 

 C=2.6 3 . 



III. Analysis of the normal Triassic diabase of West Rock, New Haven, by Mr. 

 G. W. Hawes. Am. Jour, of Sci., Ill, IX, 186, 1875. 



1 The figure here given (0.89) includes not only ferric and ferrous iron, but 

 also that in combination with sulphur, as (Cu FeS 2 ) and possibly a little FeS 2 . 

 Because of the sulphide FeO could not be estimated. (Hillebrand.) 



2 Taking the Cu as a basis the sulphides figure out 0.40 percent. CuFeS 2 . I can- 

 not say that there is any FeS 2 present. The mass of the sulphide seems certainly to 

 be chalcopyrite. (Hillebrand.) 



The whole rock will then contain, roughly speaking: 



