NILGHIEI HILLS. 233 



and which were subsequently much modified in form by marine action. 

 It is not improbable that the Neelgherries have 



Probably subsequent , . ■ ,1 



in part to the general been upheaved en masse to some extent, since the 



upheaval of the country. • i • . . r 



surface of the plateau received its present form, 



and since that portion of the country has been raised above the sea, 



for the mural escarpments which bound the Neelgherries are far more 



precipitous than we could imagine them to have been, had they been 



subjected to marine action during a long gradual process of upheaval 



from the sea. 



Of the Geological periods during which the disturbances just enumer- 



, . , , „ ated took place we can learn nothino: in this part 



Geological epoch of up- ^ = i 



heavala not ascertainable, ^f the country, there being no sedimentary rocks 

 that can furnish any clue to this important problem. 



The Carnatic, and the country through which the Godavery flows, 

 are the districts most likely to afford the much desired information as 

 to the epochs of disturbance in the Indian Peninsula.* 



In describing the great lines of fracture in the rocks of the Neel- 

 ^ , sherries, no notice has been taken of the small 



Quartz veins cannot be '^ 



classed with any system, quartz veins Occurring in various part of the 



hills inasmuch as these minor disturbances can scarcely be referred to 



any distinct system. They are in most cases of 

 Of no economic value. 



no great length or width, and of no economic 



value. The vein stone in all of them is a pure white quartz, occasionally 



• From the subsequent Siu-vey of the cretaceous rocks to the North of Tricliinopoly, it 

 is proved that the CoUamullies and PuchamuUies, two groups of Gneiss hills between 

 Trichinopoly and Salem, and about 90 miles East of the Neelgherries, have been upheaved 

 during two successive epochs of disturbance. The first of these occurred after the depo- 

 sition of the lower cretaceous series of Southern India, (a group, wliich appears to be 

 of newer date than the Keocomian rocks of Europe); the second, at some period subsequent 

 to the formation of the upper cretaceous seriea of the same district. It is possible that the 

 former of these epochs may have been synchronous with the upheaval of the ghats, and 

 that the latter, during which the disturbance was evidently more local, was contemporaneous 

 with the upheaval of the Neelgherries as a group. 



