246 



Geology of the Neilgherries. 



[No. 12, NEW SEBIES. 



A stratum of chlorite schist crops out on the surface of the Hill, 

 where the specular and octahedral iron ores occur. It has a dip 

 of about 45 degrees to the Northward. 



On the South declivity of the hill, in a pathway leading to Dr. 

 Wight's house, two distinct layers of it apart from each other ap- 

 pear which if taken as margins of the whole bed, would afford a 

 thickness to it of about 14 feet. 



It is connected with garnet rock and stratified quartz, which I 

 believe to be distinct from the vein quartz and to belong to the 

 quartz rock of the metamorphic series. 



The chlorite schist occurs in the following forms. 



1. Green chlorite schist a concretion of foliated chlorite, having 

 a pearly lustre and a highly saponaceous feel. It is soft to the 

 nail, and wants elasticity : the last three qualities distinguished it 

 from mica, which has but 9 per cent of magnesia while this pos- 

 sesses 27. 



Examined with the microscope it presents the appearance of 

 numerous small glistening scales. It loses its color before the 

 blow pipe and is fused with difficulty. 



Some specimens emit an earthy smell when breathed upon. 



2. Chlorite schist. A green slaby homogeneous base, em- 

 bedding black shining scales of mica and small plates of green 

 chlorite. 



3. Quartz and chlorite alternately laminated. 



4. Asbestiform chlorite schist, a base of foliated silky white 

 chlorite including scales of mica. 



The discovery of chlorite schist, argillaceous schist, hornblende 

 schist, and of what I have every cause to believe, metamorphic 

 quartz rock, although in inconsiderable quantities, has satisfac- 

 torily established the presence of the metamorphic or Primary 

 stratified Rocks on the Neilgherries. 



I am very sanguine that gneiss and true Mica slate will shortly 

 be found. 



In cavities of the outlaying quartz geodes are met with con- 



