UPPER GONDWANA OR JURASSIC ROCKS. 33 



One group of these veins shows near the end of higher part of the 



ridge, and when seen from a little distance present a striking resemblance 



to beds of conglomerate intercalated among sandstones. 



About 3 miles south-west of Palamcotta numerous veins of granite 



South-west of Palam- ^re seen permeating the gneiss in a very irregular 



^° ^' way. They appear to anastomose throughout the 



general mass of rock, but are very ill-seen among nearly flat sheet-like 



outcrops of gneiss ; both rocks being moreover very greatly decomposed. 



The only quartz veins that I noted occur on the western slope of 



^ . the Serumalai east and south-east of Amma- 



Quartz veins. 



nayakanur Station. They consist of pure white 

 quartz without any included minerals, and are very short and small, only 

 a few yards being exposed in each case. They contain as far as my 

 observation went no accessory minerals of any kind, and have in miner^s 

 parlance a decidedly " hungry " look. 



CHAPTER IV. 



UPPER GONDWAISTA OR JURASSIC ROCKS. 



Before the survey of the Madura and Tinnevelly district was taken 

 up, it "Was thought very likely that the broad belt of country lying 

 between the area of the gneissic rocks and the fringe of alluvium, 

 which skirts the coast line, might contain representatives of the Jurassic 

 and cretaceous rocks which form such interesting features in the 

 geology of the seaboard of the central and northern parts of the 

 Carnatic. Unfortunately no rocks were found which could be regarded 

 as unequivocally representative of either system. Two outcrops of 

 rocks, bearing strong petrological resemblance to some members of the 

 Jurassic system forming the Upper Gondwana series of the Geological 

 Survey of India, were certainly found in the Sivaganga country 

 (Madura district), but unfortunately neither outcrop yielded any fossil 

 c ( 33 ) 



