18 rooTE : geology of madura and tinnevelly districts. 



quartz gronp was therefore not followed up, nor could it be traced by the eye 



for any distance as in the Allagiri itself, where it is visible for many miles. 



The southern part of the gneissie area in Madura district can- 



^ , not be divided into groups owing to the great 



Gneiss rocks in South ... 



Madura not divisible into extent to which its surface is obscured by super- 

 ficial deposits, especially by wide spreads of 

 resrur, or cotton soil. These latter are to be met with all over the 

 southern half of the Tirumangalam taluq and over the south-western 

 part of the Ramnad zemindary. By far the greater number of out- 

 crops noted were of granitoid gneiss. But it would not be fair to 

 infer from this that schistose varieties of gneiss are not represented in 

 due proportion ; the fact being that only the highest points of the differ- 

 ent outcrops are as a rule exposed above the superficial deposits, and 

 that the harder granitoid beds show more prominent basset edges than 

 the schistose beds. Very few outcrops of any kind are seen along the 

 line of railway, or the old trunk road, to the south-ward of Tiruman- 

 galam, the spread of regur being very thick and un-broken. The 

 outcrops most worthy of note along this line are the Chevvur Kotai 

 Outcrops sontb of liill 6 miles south of Tirumangalam, and the 

 Tirumangalam. Kalligudi (Cullygody) hillocks 2 1 miles west of 



the railway station of that name, both of granitoid gneiss. 



In the latter case the pale greyish or pinkish-white quartzo-fels- 



pathic rock, banded with laminse consisting mainly 

 Kalligudi outcrop. 



of rather pale red or pink garnets of small size 



with a few spangles of mica, strongly resembles the Cape Comorin 

 rock. The rock is one of great beauty, especially when freshly quarried. 

 At the time of my visit quarrying had been carried on largely, and fresh 

 surfaces of many square yards in extent showed the lamination of the 

 gneiss in very pleasing undulating patterns. The bedding strikes gene- 

 rally nearly west and east, and has a southerly dip of from 60° to 80'. 

 The outcrops form a small group of low rocky hills to the west of the 

 villao-e of Kalligudi (Cullygoody) and about 3 miles westward of the 

 South Indian Railway Station of that name. 

 ( 1'^ ) 



