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The Geology of the. Gold Fields of British Guiana. 



Granititc, North- Western district 



,, Maziiruni River 



,, Esscquibo-Potiiro district 



Horneblende-granitite, Brirama River ... 



,, ,, Mazaruni-Puruni River 



,, ,, Essequibo-Potaro River 



Augite-granitite, Mazaruni River 



, , , , Groete Creek ... 



Augite-syenite, Demerara River ... 



,, ,, Mazaruni Rivei- ... 



Syenite, Essequibo River ... 

 Q,uartz-mica-diorite, North- Western district ... 



,, ,, ,, Mazaruni River 



Quartz-diorite, Essequibo River .. . 

 Diorite, Barima River 

 PorphjT-itic augite-hornblende-syenite, Mazaruni Riv 

 Porphyritic diorite, Mazaruni River 

 Mica-srabbro 



Toscanose. 



Alsbachose. 



Yellowstonose. 



Mariposose. 



Dacose. 



Yellowstonose. 



Kallendose. 



TTarzose. 



Yellowstonose. 



Mazarunose. 



Auvergnose. 



Tonalose. 



Placerose. 



Bandose. 



Auvergnose. 



Kedebocase. 

 Hessose. 



