GNEISSIO ROCKS. 19 



About 6 miles nortb-east-by-east of Kalligudi station at the village 

 Crystalline limestone of Tirumal is a broad (apparently double) band of 

 coarse white crystalline limestone which may be 

 traced for nearly 2 miles to the eastward, associated with much inter- 

 bedded tremolite. Much of the surface of the bed has been quarried 

 away, and what remains is not well seen, as the outcrop is very low 

 and much obscured by the local swampy alluvium under the great tank. 

 The dip of the bed (or beds) is doubtf ul, but in another bed of white 

 crystalline limestone, which is to be seen at the north end of the great 

 tank^ I mile to the north-west of Tirumal, the dip is distinctly south- 

 ward, but at a very high, angle. This bed which is only seen for a 

 distance of 30 or 40 yards is fully 30 feet thick, and has a very 

 coarse crystalline (spathose) texture like the Tirumal beds. Two small 

 Crystalline limestone ^^^^ ^^ crystalline limestone with associated tre- 

 at Kok-kulam. j^^i'^g ^^^^^ ^ j-^^j^ ^^ ^j^^ westward of the village 



of Kok-kulam (Kokolum), a mile to the north-east of the last named 

 limestone outcrop. The limestone is white and highly charged with 

 granules of pale greenish or yellowish-grey coccolite. Two small beds 

 of tremolite rock enclosing many nests of calcspar occur one in the 

 bottom of the tank west of the Tirumal ; the other to the north of the 

 village Suddumbakulam on the left bank of the Gondar. 



To the northward of this band of limestones comes a band of granite 

 gneiss which may be reckoned as belonging to the lower granitoid gneiss 

 (No. 1, page 11.) of the Madura country. Unfortunately its relations to 

 the more southerly beds of undetermined horizon could not be made out 

 as the rocks were not seen in any juxta-position. Turning southward 

 again along the high road from Madura to Ettiapuram and Tutikorin a 

 good section of very white garnetiferous gneiss (strongly resemblino- 

 many of the beds near Cape Comorin) crossing the Shevery Kotai-i^r 

 at the ford south of Vakaugoondoo. 



A band of very typical granitoid gneiss may be traced from the 



Band of granite gneiss valley of the Shevery Kotai-A'r at Shoilputty 



west of Tirushulai. south-eastward close down to Tirushulai (Tiru- 



( 19 ) 



