388 Notes, chiefly Geological, [No. 173. 



as to give them the character of dolomite. It often contains translucent 

 nodules of a siskin green nephrite. In some places, elliptic and tubular 

 cavities are observed in the massive varieties : the more exposed of which 

 are generally empty; while others are seen filled with a ferruginous 

 clay or earth, which is magnetic after exposure to heat. The elliptic 

 cavities often occur in strings. 



A bed of ferruginous sandstone is seen in the limestone, a little fur- 

 ther eastward. 



The hornblende schist has evidently been greatly waterworn near its 

 contact. Its surface, to the depth of several inches, is much weathered, 

 and has sometimes crumbled into a dark-green sandstone, cemented by 

 calcareous matter from the superincumbent limestone ; at others it 

 assumes the aspect of a rust-coloured siliceous schist, impregnated with 

 calcareous matter. Many of the loose blocks of hornblende schist have 

 been much corroded, apparently by aqueous action. 



As the edges of the limestone are left behind, and as we advance 

 soon towards the centre of its area, the disturbance and dip become less, 

 till near Kurnool, as seen in the banks of the Hendri and Tumbuddra, 

 the beds are nearly horizontal. Another change of dip, from the nearly 

 horizontal to the vertical, may be seen in the space of a few yards in 

 the limestone beds to the right after entering the western, or new gate 

 of Kurnool fort. 



The colour of the limestone at Kurnool is generally a light bluish- 

 grey, which passes into a deep blackish- blue. Near trap dykes, it often 

 becomes crystalline, magnesian, and cream-coloured; or speckled and 

 variegated with green bands, like some varieties of serpentine. 



It usually abounds with iron pyrites ; and to the right of the 

 western gate in the fosse of the fort, may be seen to imbed a fine layer 

 of red jasper, often reticulated by bluish quartz, and calcedonic veins. 

 This jasper also runs in veins, and occasionally in nodules. Near 

 this, the limestone strata have evidently undergone plutonic disturbance, 

 being elevated with waving and bending of the layers into a nearly 

 vertical position as before mentioned. 



From Kurnool to the Eastern Ghauts. — After having forded the Hendri 

 to the eastward, low rugged hills, the outgoings of a great dyke of 

 basaltic greenstone, having a westerly direction, are crossed, altering 



