48 



E53 



III 



EXPLANATION". 



1. Crystalline Schists, mostly Gneiss. 



2. Granitite. 



3. Aplite. 



4. Aplite, with occasional epidiorite. 



5. Basalt, mostly olivine-ba&alt. 



6. Nepheline-basalt in paift. 



7. Dolerite mostly, with basalt, very 

 8 Diabase. [abundant farther south. 



( 9. Felsite. 



uO. Felsite, with Quartz- and Felspar- 

 ( Porphyry, and Breccias of d:>. 



11. Trachyte, in part Nepheline-Phono- 

 (l2. ]STepheline-Pho:iolite. f llte " 



)l3. Hauyne-Nepheline-Phonolite. 

 )l4. Foyaite. 

 \15. Camptonite, or an allied ro,3k. 



16. Jurassic, sometimes oolitic limestone. 



17. Cretaceous. 



18. Eocene. 



19. Basalt-dykes. 



20. Unknown, but probably mos'ly Ju- 



rassic, covered here and there by 

 volcanic rocks. 



[The western limits of the dolerite, 

 felsite, etc. of the east coast are not 

 known, but these rocks are seen to be 

 underlain by gneiss. 



GEOLOGICAL SKET 



OF 

 EXTREME NORTI 



MADAGAS 



BY 

 Rev. R. Baron 



Scale of Miles 



NosimitsiOj 



