770 Notes, chiefly Geological, [No. 166. 



The village of Sankerry-droog now contains nearly 300 houses, 

 chiefly of Telinghi, Bulgawar, JMahomedans, Pullaywars, Yeddyers, 

 cloth- weavers, and a few Brahmins of the Madul, Smartal and Sri- 

 vaisnavam sects; the first predominating. It is worthy of remark 

 that a few Canarese families are to be found here, also a few Telas 

 and Comtis. Saltpetre and silk are manufactured here. 



The Thermometer (Faht.) placed on the naked rocks at this place, at 

 2 p. m. in a clear tranquil day, and fully exposed to the sun's rays, 

 stood at 120°, at 5^ p. m. 100°. 



About six feet above the rock's surface it indicated 110° at 2 p. m., 

 shade 90°, and at 5| p. m. 90°, shade 82°. 



On the sandy soil at 2 p. m. the mercury rose 4° higher than on 

 the rock. 



The temperature of a spring was 82 c 4. These observations were 

 made in the middle of March. 



Erode. From Sankerry-droog to Erode, which lies about If mile on 

 the right or South bank of the Cauvery, there is a gentle sinking of the 

 face of the country towards the bed of the river; the formation is 

 chiefly gneiss and hornblende schist; strike of strata towards S. 20° E. 

 and dip at an angle of 80° E. 20° N. There are many irregularities 

 and exceptions to this rule. 



The mica of the gneiss in the bed of the Cauvery near Erode is 

 dark shining and foliated. 



The surface of the rock has been scooped out by the action of the 

 water into longitudinal furrows and troughs, following the line of 

 stratification, which here happens to be parallel to the course of the 

 stream. 



An examination of the grooves and troughs is interesting in many 

 points ; and especially as demonstrating the difference caused either 

 by the action of water alone, or by gravel and sand hurried along by 

 water over rocky surfaces, in contradiction to the furrows resulting 

 from glacial action. 



The latter run on in straight undeviating parallel lines, unaffected 

 by the different degrees of hardness of the rocks, while the depth of 

 the former, and sometimes even their direction, perpetually varies with 

 the varying resistive powers of the rock, and are particularly obvious 



