h. This most interesting slide was kindly lent me by Mr. 

 R. E. Priestly. Olivine was present in some amount, 

 though now it is entirely replaced by granular quartz, grey 

 carbonates and greenish silicates. In one portion the 

 olivine is irregular in outline and includes within it a grain 

 of plagioclase, from which as from the surroundiug felspar 

 it is separated by a narrow band of diopside containing 

 pleonaste. This surrounding of an olivine grain by diopside 

 is of frequent occurrence in the slide and the outgrowth of 

 pleonaste from the boundary of the plagioclase into the 

 pyroxene crystal is very well marked. Both rhombic and 

 monoclinic pyroxene may contain the pleonaste. In one 

 instance olivine is separated from plagioclase by a large 

 crystal of pleonaste. It is to be noted that the olivine does 

 not appear ever to contain spinel. The plagioclase is a 

 labradorite-bytownite. 



i. and j. were kindly lent me by Mr. 0. A. Siissmilch. i. 

 contains a small amount of greenish decomposition product, 

 probably after olivine, included in a large aggregate of 



