XLl 



CONTENTS 



7. The Peridotite-Limburgite Group . 



8. The Pyroxenite-Augitite Group . 



9. The Leueite-Nepheline Rocks 



II. Aqueous Bocks 



1, Rocks fonned through Chemical Agencies 



(1) Oxides 



(2) Carbonates . 



(3) Silicates 



(4) Sulphates . 



(5) Phosphates 



(6) Chlorides . 



2. Rocks formed as Sedimentary Deposits . 



(1) Rocks composed mainly of Inorganic Material . 



(1) The Arenaceous Group : Psammites 



(2) The Argillaceous Group: Pelites , 



(3) The Calcareous Group: Calcareous Con- 

 glomerate and Breccia .... 



(4) The Volcanic Group: Tu:ffs . 



(2) Rocks composed mainly of debris from Plant 



and Animal Life 



(1) The Siliceous Group: Diatom Earth 



(2) The Calcareous Group: Limestone, Marl, 

 exc» »•••••»• 



(3) The Carbonaceous Group: Peat, Lignite, 



and Coal 129 



(4) The Phosphatie Group .... 131 



III. MouA-N Rocks 133 



Volcanic Dust; Dune Sands, etc 133 



IV. Metamokphio Rooks ... .... 135 



Agencies and Results of Metamorphism and Metasomatosis 135 



1. Stratified or Bedded .... . 141 



(1) The Crystalline Limestones and Dolomites 141 



2. Foliated or Schistose 142 



(1) The Gneisses 142 



(2) The Crystalline Schists . . . '. 146 



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