140 Notes, principally Geological^ on Southern India. [Jan. 



Peroof.—At Peroor, a village situated upon the eastern bank of tlie 

 Pennaur, the range on the right ceases altogether, while that on the left 

 or west (the Condaganpilly range), wears a smoother aspect, and turns 

 off to the west. The quartz rock mentioned at Terimany, here occurs 

 in situ, in a bed of a nullah, a little to the east of the fort : it rests un- 

 comformably in almost tabular masses on the surface of the gneiss. It 

 is loth massive and schistose, according to position ; massive when 

 seen in blocks protruding from the surface of the soil, and schistose, 

 generally, when found in contact with the gneiss. A thick bed lies at 

 the bottom of the nullah. In structure it varies from that of gneiss, 

 to that of the red granular quartz rock of Cuddapah, and contains but 

 a minute portion of mica. The gneiss is generally much weathered, 

 and abundantly seamed by incrustations of kanker. Its strata are not 

 60 much inclined as hitherto, having a dip oi about 25° to the E. S. E.— 

 direction as before. Beds of the micaceous hornblende schist are seen, 

 commonly with the same dip and direction as the gneiss. The greenish 

 eurite and accompanying pegmatitic veins, like the basalt, frequently 

 intersect the line of direction at considerable angles. They are of more 

 recent date than the quartz veins, as is shown by their passing through 

 them. At the points of contact, faults or dislocations are sometimes 

 seen in the latter ; an instance occurs in the gneiss of this nullah. 

 The dislocation is of a few inches, in a W. N. W. direction. Granite 

 is still seen in detached masses. Beds of the micaceous hornblende 

 rock are observed in the wells, disintegrating into a greenish friable 

 substance, and exhibit various stages of decomposition in the same 

 mass. The mica is seen more distinctly in the decayed portion; 

 it changes to a silvery brown which gradually loses its brilliancy. The 

 hornblende decomposes with the felspar, into a light dirty green 

 friable rock, mottled with ferruginous spots. Probably the hornblende 

 is combined with actynolite, which not only gives the rock a schistose 

 character, but imparts much of the green in decomposition. The 

 curite near this mass does not appear to be in the slightest degree 

 altered. This rock, like basalt, is more crystalline in the middle of 

 large veins. In small veins it becomes compact, heavy, extremely tough* 

 and shows a disposition to split into rhomboids. Crystals of epidote 

 occur in the gneiss near the greenstone dykes. 



Eampur, — This place is situated on the right, or western bank of 

 the Pennaur, which is here upwards of 200 paces broad, taking a bend 

 to the east. Its bed is of sand, from which the subjacent gneiss and 

 micaceous hornblende slate occasionally protrude. The surrounding 

 country consists of undulating plains, interspersed with a few scattered 



