248 Geology of the Neilgherries. [No. 12, new sebies. 



Rocks. 



1. Large grained granite consisting of Felspar, quartz, and 

 black mica. 



2. Compact granites. 



3. Decayed granite of Felspar and quartz with rifts throughout 

 the mass which probably once contained mica. 



4. A granite consisting of quartz and Felspar. 



5. Garnet rock sometimes occurring in columnar masses. 

 6 and 7. Syenites of various hues, and green stone. 



The following interesting varieties of overlying rocks occur in 

 outlying masses near the pass above alluded to. 



8. A combination of compact Felspar, quartz, white mica, and 

 hornblende ; associated with. 



9. A combination of opalescent, and amethystine quartz, 

 mica, garnets and Cinnamon stone. 



10. A combination of Amethystine quartz, common quartz, 

 pearly white Felspar, black and gold coloured mica, Cinnamon 

 stone, and green hornblende. 



The three last rocks are remarkably beautiful. 



11. Common Felspar and hornblende. 



Mines alb. 



1. In some stratified blue quartz accompanying common gar- 

 nets, occurs a garnet of remarkable and unusual form, being a six- 

 sided prism with terminations of three sided pyramids. Notwith- 

 standing its prismatic structure the crystal like the common garnet 

 retains twelve rhomboids. 



No molecular replacement will account for this deviation from 

 the characteristic form of the garnet, and I can only imagine two 

 garnets to have united. Some of the crystals of this mineral are 

 tinged with a smoky blue colour. 



2. Idocrase which occurs in Syenite* 



3. Hypersthene occurs in the rock marked 4 in the preceding 



catalogue. 



