52 GEOLOGY OF THICHINOPOLY, &C. [ClIAP. IV. 1. 



they form laminae running through the mass of the rock. Chlorite 

 occurs largely in some of the pink limestone, dotting the surface with 

 bright green, while glittering scales of yellow Mica replace this mineral 

 in the white varieties of the limestone. Detached pieces of gneiss and 

 nests of quartz sometimes occur enclosed in the limestone, but these are 

 very rare. 



A small but very interesting development of crystalline limestone 

 occurs on the upper and now almost abandoned road 

 from Trichinopoly to Caroor, 1 j from the travel- 

 lers'* bungalow at Poodoopolliam, to the south-east, and close to the 

 village of Culputty. It appears at a point where the quartzose gneiss 

 has undergone considerable contortion, the strike of the folia curving 

 round from south-east to north-north-east (E. 45° S. to E. 68° N.) in the 

 space of a few hundred yards. There are, close to this, many small and two 

 or three moderately-sized granite veins running north and south across 

 the general line of strike of that locality, which is west-north-west to 

 east-south-east. But these do not appear to have been in any way the 

 cause of the disturbance which is observable. At this place there are three 

 small bands of limestone running in a north and south direction across the 

 high road, with a westerly dip of about 40°, and apparently uniting a 

 few yards to the north of the road, when the main bed continues its course 

 for about one hundred and fifty yards, and disappears under the surface 

 debris, only a few yards before the gneiss beds, which are seen a little to 

 the west, are deflected by a sudden curve to the north-east by north. 

 (N. 32° E.) 



The greatest width of the beds is shown on the road. The most 

 easterly bed is about 12 feet wide, and this continues for about 60 

 paces until it joins the main bed. This main bed is about 8 feet 

 in width and 200 yards in length; and the westerly bed, seen 

 only on the road, is about 5 feet wide. The limestone is compact, 

 rather fine-grained, and of white colour, sometimes with a grayish, or a 



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