Chap. III.] trichtnopoly district — crystalline rocks, 31 



marked with conspicuous ridges of bare rock, ]3ink and glittering 



with abraded quartz and felspar (Orthoclase,) stretches for many 



miles along the North flank of the alluvial valley ; its course, 



(nearly East and West,) coinciding with that of the river and that 



of the gneiss folia and bedding, over the whole 

 Its direction, 



of the low country between the Collamullays 



and the hills of Madura. To the Westward this granitic band has 

 and extent to the ^een traced* in undiminished breadth as far as 

 ^® ^*'' ' Caroor, and there is reason to believe that it 



extends much further : granite veins are found in the neighbourhood 

 of Coimbatoor : and as the gneiss, with the local structure of which 

 it is intimately connected, pursues the same East and West strike 

 across the Peninsula, as far at least as the Palghat gap, it is not impro- 

 bable that the granite of Coimbatoor may be a portion of the band 

 I have described. 

 To the East of the Madras road it may also be traced as far as any of 



the Crystalline rocks are exposed, viz. to the 

 and to tlie Eastward. 



village of Shuthamungalum, where it disappears 



beneath the Cretaceous rocks. To the North-east of Samiaveram it rises 



considerably above the average level of the surrounding country, its highest 



point, Thutchuncoorchy hill, and a great part of its 

 Its elevation. 



undulating surface, being probably not less than 



300 feet above the level of the Cauvery. This elevated granitic tract is 



an important feature in connection with the Physical Geography of the 



Cretaceous rocks. Of the date of the intrusion of the granite we know 



Date of granitic intru- ^^* ^^^*^®' beyond the fact that it must have been 

 sion unknown, long, probably very long, anterior to the formation 



of any of the existing local sedimentary formations ; and that it w^as 

 possibly coeval with the gigantic disturbances which folded up the gneiss 

 into great contortions, 



* By Messrs, King and Foote, 



