34 N. L. Bowen — Alnoitic Rocks. 



EXPLANATION OE PLATE I. 



a. Zoned melilite with isotropic core and birefracting (negative) rim; 

 x 20. Melilite-biotite rock, Isle Cadieux. 



b. Eemnants of a single pyroxene crystal (P, P) in matrix principally 

 of biotite; x 67. Monticellite alnoite, Isle Cadieux. 



c. Eesorbed chrysolite crystals (chadacrysts) in matrix (a single 

 oikokryst) of biotite showing rims of ore at borders of chrysolites; x33. 

 Alnoite (approaching mica peridotite), Isle Cadieux. 



d. Eesorbed pyroxene crystal (P) in matrix principally of monticellite; 

 x 20. Monticellite alnoite, Isle Cadieux. 



e. Blocky replacement of a pyroxene crystal by biotite; x 20. Monticel- 

 lite alnoite, Isle Cadieux. 



/. Eesorbed chrysolites (c) surrounded by similarly oriented monticel- 

 lite (M) ; x 33. Alnoite from Aldersnaset, Alno. 



