Bock-3fe(amorphis>n.] 



K. 1. 



[To face p. G8. 

 Pig. 2. 



Fig. 3. 



Fig. 1. Diagrammatic transverse sections of a prismatic crystal of peridote. 

 Obtuse angles 94 j acute angles 86. The outer dotted lines represent 

 the form of its primary j the inner continuous lines angular measurements 

 of its simplest modification ; the broken lines its rectangular cleavage. 

 The prism is upright. 



Fig. 2. Diagrammatic transverse sections of a prismatic crystal of augite. 

 Obtuse angles 92 55' ; acute angles 87 5'. 



Fig. 3. Diagrammatic transverse sections of a prismatic crystal of hornblende. 

 Obtuse angles 124 30'; acute angles 55 30'. 



The augite and hornblende prisms (Figs. 2 & 3) are inclined (mono- 

 clinic). Their inclination to be assumed as from bottom to top of the 

 page. When their angles are truncated down to the white lines, the 

 resulting section is that of the usual prism. 



The outer dotted lines represent the form of the primary ; the con- 

 tinuous lines a secondary form, or that of the cleavage-solid j the broken 

 lines the cleavage, which is rhombic. 



