CON T E N T S . 
Page. 
Chapter I. Introduction 7 
Chapter II. The theory of the silicates 12 
Chapter III. The orthosilicates of aluminum 18 
I. The nephelite type 18 
II. The garnet-biotite type 20 
III. The feldspars and scapolites 28 
IV. The normal zeolites 32 
V. The micas and chlorites : 45 
VI. The tourmaline group 56 
VII. Miscellaneous species 63 
Chapter IV. The orthosilicates of dyad bases 68 
Chapter V. The orthosilicates of tetrad bases 75 
Chapter VI. The diorthosilicates 81 
Chapter VII. The meta- and dimetasilicates 85 
Chapter VIII. Summary 101 
Index 107 
