224 



NILGHIRI HILLS. 



trace this for any distance, and the mineral bands either become lenti- 

 cular or break up and die away in the mass. 



Another variety of the foliated rocks, although not occurring on the 

 hills, must be mentioned, both on account of its 



Coimbatoor Limestone, g^jo^^jjo^ic importance, and because it exhibits the 

 banded structure more clearly than any of the other varieties referred 



Fig. 11. — Thin alternations of limestone and gneiss, weathered ; — near Coimbatoor. 



to. This is the Crystalline Limestone, a notice of which has already 

 appeared in the Madras Journal of Literature and Science.* It oc- 

 curs about five miles to the South of the Station of Coimbatoor, form- 

 ing a band of variable thickness which passes in an E. N. E. direction 

 along the foot of the broken range of hills which forms the extreme 

 Southern termination of the Neelgherry hill district. These hills, 

 Banded structure of which run parallel to the limestone band, and also 

 adjoining hills. ^^ ^.j^^ foliation of the gneiss in this part of the 



District, consist of repeated alterations of crystalline limestone and gneiss 

 in bands of from one to a few inches in thickness, and the unequal 

 erosion of the limestone and gneiss has given the hills a jagged ap- 

 pearance, very apparent when viewed in the direction of the bands of 

 structure. Two sketches illustrating this are here given (Figs. 2 & 3). 



* New Series, Vol, III, No. V. 



