8 CONTENTS. 



Chapter III. — The Agents of Metamorphism — Continued. Page. 

 Part II. Aqueous solutions and solids — Continued. 



Section 2. Circulation and work of ground water — Continued. 

 Circulation of ground water — Continued. 



The factor opposing water circulation 153 



General statements _ 154 



Geological work of ground water _ _ 156 



Chapter IV. — The Zones and Belts of Metamorphism. 159 



General considerations 159 



Zone of katamorphism 160 



Belt of weathering 163 



Belt of cementation _ 164 



Belts of weathering and cementation contrasted 166 



Zone of anamorphism 167 



Relations of zones of katamorphism and anamorphism _ _ 170 



General considerations _ 186 



Relations of zones of katamorphism and anamorphism to zones of fracture and flowage . . 1S7 



Upper limit of zone of flowage _ 187 



Chapter V. — Minerals 192 



Section 1. Chemical and mineral composition of the known crust of the earth 192 



Section 2. General nature of alterations 202 



Alteration without change in chemical composition 202 



Molecular rearrangement _ 202 



Simple recrystallization 202 



Alteration with change in chemical composition 202 



Alteration without addition or subtraction of material 203 



Alteration with addition or subtraction of material _ 203 



General statements 206 



Section 3. Bock-making minerals 207 



Manner of treatment 207 



General statements _ 207 



Native elements 212 



Graphite . ... 212 



Occurrence 212 



Alterations 212 



The sulphides 212 



Pyrrhotite, pyrite, and marcasite 213 



Occurrence 213 



Alterations 214 



The fluorides 216 



Fluorite „ 216 



Occurrence 216 



Alterations 216 



The oxides 217 



Quartz 21 7 



Occurrence 21 7 



