Washington — Study of the Glaucophane Schists. 37 



The analysis (ISTo. I, below) shows a decidedly basic com- 

 position, with rather high A1 2 3 and CaO, considerable Na 2 0, 

 and only a trace of K 2 0. It will be seen later that it resem- 

 bles the analyses of several other occurrences of these rocks. 



As the mineralogical composition is quite simple, it may be 

 calculated out quite readily as follows. The figures for 

 glaucophane used here are those furnished by an analysis 

 given further on, while those for epidote are based on the 

 analysis by Luedecke.* 



Glaucophane 37*2 



Epidote .._ 40-2 



Chlorite _. 7'7 



Quartz 6*1 



Calcite 5*1 



Feldspar 2*1 



Titauite and rutile 1*6 



100-0 



In II there is given an analysis of another specimen from 

 Syra, an omphacite-zoisite rock, composed of bright, grass- 

 green omphacite (diallage) in blades and large crystals, white 

 mica (paragonite), and granular zoisite, with a little interstitial 

 quartz. The content of mica varies considerably, being fairly 

 abundant in the specimen analyzed, and much less so in others. 



This resembles I very closely, though Fe 2 3 is considerably 

 higher than FeO. Ti0 2 was not determined, and is included in 

 the A1 2 3 . Even thus the latter is high, but is to be attributed 

 to the abundant zoisite and paragonite. The mineral composi- 

 tion of this calculates out approximately ; 



Omphacite .__ ___ 31*7 



Zoisite 31*7 



Paragonite. 31*0 



Quartz ... 5*6 



Mica- Glaucophane Schist. — The rocks which may be refer- 

 red to this group are not abundant, but vary considerably in 

 character, and, through decrease in the amount of mica tend 

 to become quartz-glaucophane schists. The specimen which 

 was chosen for analysis seemed to be fairly typical. It came 

 from near the Cafe Skarbeli, on the east coast, a short distance 

 to the north of Hermoupolis on the east coast. 



It is markedly schistose, and shows megascopically glau- 

 cophane, white mica, greenish epidote and diallage, and small 



* Luedecke, op. cit., p. 262. 



