[HOWARD] SOME OUTLIERS OF THE MONTEREGIAN HILLS 77 



Large titaniferous ajugite crystals several millimetres in length 

 predominate. This mineral has been partially resorbed and altered 

 to serioite, calcite, chlorite, and iron ore around the borders and along 

 cracks. 



A deep greenish brown biotite is also present in irregular grains 

 up to two millimetres in length. This mineral has not suffered so 

 much alteration as the augite, but, apparently, fragments have been 

 broken off and scattered through the groundmass together with 

 augite and much of the chlorite which formed around the borders 

 of the augite. 



The groundmass is composed of these fragments of biotite, 

 augite, and chlorite together with irregular grains of black iron ore 

 and a base which has been totally altered to calcite. 



This dyke may bear the same relationship to the eastern breccia 

 as that on the road bears to the breccias west of the Monastery. 

 That is, it may represent a part of the channel through which the 

 magma forming the paste of tHfe breccia surged and into which the 

 ferro-magnesian constituents settled after partial crystallization. 



Chemical Analysis of the Biotite Limhurgite, La Trappe. 



Analysis by E. P. Dolan 



SiOo 30.78 Norm 



AI2O3 1.49 Le 3 05 



FeaOa 5.64 Ne 2.27 



FeO 10.34 Ac 6.93 



MgO 16.35 Ns 2.81 



CaO 22.02 01 36.98 



NaaO 2.85 Cs 23.99 



KoO 0.67 Mt 4.64 



H2O 0.98 . II 6.38 



COo 2.78 Ap 5.04 



Ti02 3.33 — 



P2O5 2.07 CO2 equivalent to 6.30% 



MnO 0.10 CaCOa 



99.40 Classification 



Perfemane 

 dopolic 

 domolic 

 calcimiric 

 domagnesic 

 Spec. grav. 3.17 V. (1)2. 4(5). (2)3. 2 



