250 



Geology of the Neilgherries. [No. 12, new series. 



so much iron that several of the peas will attach to each other in 

 a string depending from the magnet. 



11. Red iron glance in pyramidal concretions. 



12. Variety of reddle resembling rouge (undescribed.) Has a 

 red streak and reddens paper like red chalk. Is very soft and 

 easily shaped by the knife. Structure lamellar, and easily sepa- 

 rated into thin plates. Lustre shining. Becomes black and me- 

 tallic after roasting when it is taken up by the magnet. Is a com- 

 bination of iron, oxygen, water-silica, and alumina. 



13. Sulphuret of iron three varieties. 



Var. 1st. Color different shades of grey. Dull, but fractured 

 surfaces present a] white metallic lustre. 



In the matrass gives off fumes which possess the odour of sul- 

 phur, and sublime on the neck of the tube. The result after 

 roasting is raised by the magnet. Somewhat resembles white py- 

 rites. Occurs in a rock of green syenite accompanied by the fol- 

 lowing — 



Var. 2nd. Externally resembles sulphur; of a yellow color, 

 very brittle. When rubbed between the fingers leaves a sulphur- 

 ous smell. Roasted it evolves sulphur and leaves a metallic scoria 

 acted on by the magnet. 



Var. 3rd. Investing the foregoing which it resembles in every 

 respect except color which is a greenish brown. After very care- 

 ful examination I could detect no arsenic in any of the foregoing 

 sulphurets. 



14. A green iron ore of which I can find no description in the 

 works of the English and German mineralogists. It bears a con- 

 siderable affinity to those varieties of talc described by Gruner and 

 Vauq as containing 25 per cent, of oxide of iron. Has a shining 

 pearly lustre. Color a beautiful apple green changing according 

 to the position the mineral is held in. Structure micaceous. Oc- 

 curs in flat hexagonal prisms, the angles of which are obliterated 

 and amorphous. Is soft and unctuous. Xo action takes place in 

 muriatic acid, though a feeble effervesence is perceptible when 

 the mineral in powder is immersed in sulphuric acid< Gives of 

 water in the bulb tube. After submission to the reducing flame 



