172 



On the Beryl Mine of Paddwor. 



[July 



the Shevaroy and Salem Mountains to the east. All these ranges con- 

 sist of normal rocks, principal!}^ gneiss, hornblende- slate, and mica-slate, 

 asso( iated with granite, greenstone, and basalt in dykes. The rocks that 

 occur in the plain are of a similar description, with beds of quartz dis- 

 tinctly stratified, sometimes highly ferruginous, and passing into garnet 

 rock, ('nrnets, regularly crystallized, often occur in the gneiss and horn- 

 blen^^e slate. Primitive crystalline limestone and atalcose rock occur, though 

 rarely, iriterstratified with the gneiss and hornblende slate. A remarkable 

 feature is :he jirevalence of basaltic dykes, accompanied by large traver- 

 tine and tuia-like deposits of carbonate of lime. The influence exerted by 

 the?e d> kes over crystalline and metalliferous developments in thigse dis- 

 tricts is interesting and instructive. Dykes, or veins, of a porphyritic gra- 

 nite too, traverse the gneiss in various directions. The larger veins are ge- 

 nerally from W. to E., varying a few degrees to the S. of E. The metallic 

 ores and minerals found associated with these rocks are chiefly the mag- 

 netic or black iron ore, disseminated and interstratified with quartz rock 

 3n a state of great purity. It sometimes occurs in octahedral crystals, 

 with a whitish micaceous looking enduit. Both varieties are often highly 

 magnetic with polarity. Manganese also occurs in the form of the black 

 oxide ; also garnets, corundum, magnesite, nephrite, asbestus, chromate 

 of iron, adularia, pyrites, &c. Rubies have been found associated with 

 the corundum which occurs imbedded in gneiss. I am not aware that 

 the other beautiful variety of rhomboidal corundum, viz. the sapphire, 

 has ever been discovered ; but, from certain indications, I should be led 

 to suppose its existence. Gold-dust is found in many of the rivulets 

 flowing down the sides of the Nilgherry and Salem Mountains. 



I will now proceed to describe the bed, and minerals with which the 

 Eeryl is more immediately associated in the particular locality which has 

 already been adverted to, viz. Paddioor. The mine has been sunk 

 through a bed or dyke in the gneiss and mica-slate on the line of contact ; 

 it is about eighteen paces long, by fourteen broad ; it has about seven 

 feet of water covering the lower part, and is about twenty-four deep to 

 the surface of the water. The dyke is composed of a highly crystalline 

 porphyritic granite, the component minerals of which are generally 

 beautifully characteristic and distinct. The quartz is sometimes regularly 

 crystallized, but usually in amorphous translucent masses, imbedded in 

 large tabular crystals of pale rose-coloured felspar, with cleavlandite, 

 garnet, and white, black, and bottle-green mica. A crystallized pyrami- 

 dal prism of quartz that had been dug out of this mine measured 2 feet 

 3| inches in length, and 1 foot 3 inches in diameter ; it had, however, 

 been fractured, and four only of the sides were tolerably perfect. The 



