TABLE OF CONTENTS. 
Page, 
Introduction - — 71 
Part I. Phenomena of Crystallization - 72 
Rock structures in general terms - 72 
(1.) Glassy rocks-- 72 
— without porphyritical crystals- 73 
— with “ “ _- 73 
(2.) Holocrystalline (completely crystallized) rocks-- 73 
— with porphyritical crystals- 73 
— without 11 11 - 74 
(3.) One or more generations of crystals- 74 
(4.) Special structures- 74 
Component minerals _ 74 
(1.) Their variety_ 74 
(2.) Chemical character_ 75 
(3.) Association in various kinds of rocks_ 75 
Character of the minerals as crystals _ 76 
(1.) External characters- 76 
Form and relative age_ 77 
— in glassy rocks_ 77 
— in holocrystalline rocks_ 78 
— intergrowths _ 78 
(2.) Internal characters_ 79 
Inclusions_ 79 
— kinds: gaseous_ 79 
fluid_ 79 
glassy-.- 80 
crystallized _ 80 
— mode of occurrence__ 80 
abundance_ 80 
kind and association_ 81 
arrangement_ 81 
Zonal structure_:_ 81 
— isomorphous shells_ 81 
Relations between the mineral crystals _ 82 
(a.) Association as inclusions and inter growths _ 82 
(1.) As inclusions_ 82 
(2.) As intergrowths (synchronous growths)_ 82 
(3.) As parallel growths (successive growths)_ 83 
(b.) Order of crystallization _ 84 
(1.) One period_ 84 
(67) 
