CONTENTS. 



Chapter YJII.— continued. 



Syenite ......... 



Augite-syenite 



Mica-gabbro ......... 



Gabbro .......... 



Norite 



Mica-norite 



Elvans in the Granitites ...... 



Chemical Compositions of the Aplite, Granite, Gianitite, 



Dioi'ite and Gabbro ...... 



Contents of Gold of the Aplite, Granite, Granitite, 



Diorite and Gabbro ...... 



Mineralogical Compositions of the Aplite, Granite, G 



Syenite, Diorite and Gabbro .... 

 Classification of the Aplite, Granite Granitite, Syenite 



and Gabbro ....... 



I'^yenite, 

 Syenite, 

 I'anitite, 

 , JJiorite 



Chapter X. — The Petrographu <>f lite Ldruslve Diabaxe 



Monntain Masses ........ 



Dykes and Sills ......... 



Olivine-diabase ......... 



Quartz-diabase and Augite-granophyre .... 



Basaltic-diabase or Tholeite ....... 



Tachylite .......... 



Chemical Composition of the Diaba.se .... 



Contents of Gold of the Diabase ..... 



The Mineralogical Compositions of the Diabase 

 Classification of the Diabase ...... 



Chapter XI. — Recent Formations ....... 



The Fluvio-marine Deposits ...... 



The Eesiduary Deposits ....... 



Kaolin ........... 



Laterite .......... 



Concretionary Ironstone ....... 



Movements of the Eesiduary Deposits .... 



Chapter XII. — Descripth-e Geology. The North-Wcstcin District 

 The Amacura River 

 The Aruka Eiver 

 The Barima Eiver 

 The Barama Eiver 

 The Waini Eiver 

 The Pomeroon Eiver 

 The Goldfields of the North- West District 



73 

 73 

 74 

 74 

 75 



76 



78 

 7!J 

 81 



Ch.vpter IX. — Tlie Petrograpliij of tJte Clastic Pocks, Sandsto/ics and 



Conglomerates ......... 8o 



Contents of Gold of the Sandstones and Conglomerates . . 84 



86 

 90 

 91 

 92 

 92 

 93 

 93 

 95 

 96 

 97 

 98 



99 

 99 

 99 

 100 

 100 

 102 

 103 



1 U6 

 106 

 107 

 108 

 110 

 111 

 112 

 112 



Chapter XIII. — Tlic Lower Essctjidbo River and Ctii//nd 

 The Supinaam Creek .... 

 Tiie Groete Creek .... 



The Groete Creek and Cuyuni Trail 

 The Cuyuni Eiver .... 

 The Arimu Creek 



fiirrr /)> strict 



115 

 115 

 118 

 119 

 120 

 131 



