520 Notes, chiefly Geological, [No. 163. 



nearly meet, being connected by a high and massive embankment of 

 stone and mud. These ridges have already been described, (Madras 

 Journal of Literature and Science.) 



A dyke of basaltic greenstone crosses the plain between Bijanugger 

 and Hospett in a westerly direction. It forms an eminence, on which 

 is situated an ancient Mahomedan burial ground, a little to the W.N. W. 

 of Camlapoor. 



Granite blocks, with much red crystalline felspar, are seen in the 

 ditch of the fort of Hospett. 



Proceeding towards Humpsagur, the road lies along the stone em- 

 bankment just mentioned. Gneiss is seen immediately at the eastern 

 base of the hills, but their bulk is composed of a dull green horn- 

 blende schist, with much silex and argillaceous matter, crested by a 

 jaspideous rock similar to that cresting the Copper mountain. This 

 rock contains nests, and layers of iron ore and loadstone, or iron ore 

 with polarity. This I first discovered in setting down my pocket com- 

 pass on one of the ferruginous-looking masses which project from the 

 surface of the mammiform hill overlooking Hospett, when I was surprised 

 to see the north pole of the magnet whirl suddenly round to the south, — 

 a hint to be careful in selecting spots for taking magnetic bearings, 

 choosing a site for an observatory, or in selecting stones for the fixed 

 stands of magnetic instruments, &c. 



Quartz, both white and ferruginous, is abundant ; and a white striated 

 mineral resembling tremolite externally. 



Wallavapur. This place is about thirty miles from Hospett. Below 

 the fine anicut (dyke) thrown across the river by the Hindoo princes of 

 Bijanugger, is seen a bed of gneiss penetrated by veins of porphyritic 

 granite, containing much pink felspar in large semi-foliated crystals ; 

 and here and there nests of hornblende and mica. The strata of the 

 gneiss are waved and bent. 



A dyke of basaltic greenstone crosses the river bed in a westerly 

 direction, compact at the edges : porphyritic towards the centre. The 

 imbedded crystals are of light green felspar augite and hornblende. 



Gneiss, granite, hornblende schist, and basaltic greenstone continue 

 to Humpsagur, where the Tumbuddra is crossed, into the South Mahratta 

 country. 



