40 



NEW YORK STATE MUSEUM 



clase, quartz, garnet, magnetite and pyrrhotite as the chief com- 

 ponents. Apatite of course appears in occasional crystals, and 

 biotite is moderately frequent at times and again rare. The same 

 is true of hornblende. The individuals, except for the rare pheno- 

 crysts rarely reach i millimeter in diameter, ranging from .25 to .5 

 millimeter. They are irregular in shape so that the rock is finely 

 granitoid in texture. It is rather dark gray in color and is strongly 

 contrasted with the anorthosite against which it lies. The rock has 

 undoubtedly been granulated to an appreciable degree by pressure 

 and crushing. The edges of the components frequently show 

 strains under crossed nicols. 



Two analyses have been prepared of the gabbro, one from a 

 locality just below the dam at the mill, no. 2 ; and the other, no. 3, 

 of a more acidic phase farther up stream. No. 2 is by Dr W. F. 

 Hillebrand and was made in the laboratories of the United States 

 Geological Survey; no. 3 is by Dr C. A. Jouet in the laboratories 

 of Columbia University. No. i is the anorthosite and is repeated 

 from p. 36. 



Si02 



AI2O3 ... 

 Fe203 • • • ■ 



FeO 



MgO .... 

 CaO .... 

 NaoO ...■ 



K2O 



H2O+ ... 

 H2O— . . . 



CO2 



Ti02 .... 



P2O5 



MnO ... 

 BaO 



S 



NiO.CoO 



56 



94 



20 



82 





83 



3 



02 



2 



36 



9 



41 



3 



36 



I 



58 





59 





21 





45 





44 





07 





II 





05 







2 



3 



47.16 



50-54 



14-45 



21.28 



1. 61 



3-43 



i3-8i 



8-73 



5-24 



2.08 



8.13 



8.72 



3.09 



2-95 



1.20 



1.63 



.48 



•35 



.12 



.06 



•35 



present 



3-37 





•57 





.24 



.40 



.14 



02 



.64 



100.24 



99.98 



100.81 



Quartz 

 Or ... 

 Ab ... 

 An ... 

 Kaolin 

 Calcite 



I 



2 



7.20 





9-45 



7-23 



28.30 



26 . 20 



32.80 



18.07 



4-39 



3-43 



1. 00 



.80 



2 





3 



60 



7 



23 



25 



15 



27 



80 



2 



58 



