GNEISSIC ROCKS. 21 



About 4 miles south of Palavanattam lies a small hill of bare rock 

 rising on the top of the watershed between the 

 valleys of the Virudupatti and Shenkotai rivers. 

 This hill which is known as the Kotaiparai (Koteaupaurse Trigonometrical 

 Station) is remarkable because consisting of dark hornbleudic granite 

 gneiss which is a very rare rock in this quarter. It rises out of the middle 

 of a great and unbroken spread of cotton soil. 



A great many outcrops of banded granite gneiss of no special beauty 

 or noteworthy colour are to be seen on the high ground at and east and 

 south-east of the village of Kalurani (Kulloornee) 4 miles south-east 

 of Aruppukotai. To the south of Aruppukotai, close to Vala Vangal 

 (Shevandapuram of map), is a show of very perfectly banded granite 

 gneiss, both micaceous and hornblendic, striking north-west to south- 

 east in almost vertical beds. 



Four or 5 miles further south of Shevandapuram and a mile south 

 Pantalagudi crystal- 0^ Pantalagudi (Punthulkgoody) the high road 

 ine limestoue beds. ^^^g across a very large and important bed of 



crystalline limestone which I traced north-west-by-north for upwards 

 of 3 miles cropping up through the thick cotton soil which covers 

 nearly the whole surface in that quarter. The thickness of the great 

 bed is not easy to ascertain, owing to the extent to which it is obscured 

 by the cotton soil. I paced it at several points where best seen, and 

 found it to average about 50 yards, the narrowest part being 37 and 

 the widest 73. The limestone is generally of very coarse grain, so 

 much so as in parts really to deserve the appellation of calcspar rather 

 than crystalline limestone. This is more especially the case at the 

 southern end where the predominant colour is pale grey or white. In 

 the northern part of the bed its eastern or upper part is reddish or 

 pink in colour and rather close grained. The dip where best seen at the 

 southern end is from 65° to 70° north-easterly. The only included 

 accidental minerals noted were occasional small granules of pale coeco- 

 lite and spangles of graphite. About | of a mile west of the northern 

 end of the great bed is a small outcrop of white crystalline limestone 



( 21 ) 



