INTRUSIVE ROCKS IN THE ARCH^AN AREA. 175 



tensely decomposed to a great depth. The quartz at the west 

 end of the great ridge is much whiter and purer than at the foot of 

 Siddapan Konda, where it is so impure as not to be easily distin- 

 guished from the rotten country rock. Eastward of Siddapan 

 Konda the ridge falls off rapidly and is cut through by a small stream 

 flowing northward. A mile further eastward yet, the three parallel 

 runs seen at the foot of Siddapan Konda 1 rise again distinctly, but do 

 not attain to any great elevation, probably not to 100 feet above the 

 surrounding country. In the highest tor standing on the top of 

 the main ridge the quartz shows slight stains of copper green ; and 

 in the quartz close by are enclosed numerous small crystals of pink 

 felspar (see page 168). The mass of the quartz has in parts assumed 

 a cherty look, which seems to be owing to the presence of very 

 minute quantities of very finely divided chlorite which pervades the 

 quartz like a cloud. 



None of the other runs offer any points of special interest, but 

 Other important runs there are several that may be noted for their 



south of Harappana- . . ... 



halli. great size either in length or height, or both. 



Among these are the two great runs forming the southern side of 

 the fan-shaped group of runs which radiate westward from a point 

 some 3 miles east-south-east of Harappanahalli town. The more 

 southerly of the two has a course some 7 miles long and forms con- 

 siderable ridges in its eastern and western parts, the central part 

 being much lower. Another group of large and conspicuous runs 

 occurs in the southern part of the Harappanahalli taluq between 

 Teligi (Tellyghee) and Uchingi drug. 



Two high runs form the bold rocky crests of the Ujinni (Oojinny) 



Ujinni and Nimbal- an d Nimbalgiri hills, both of which rise some 400 



gln runs * feet above the surrounding country, reaching 



respectively, the heights of 2,370 feet and 2,650 feet above sea level. 



These occur quite in the south of the Kudligi taluq, while to the 



, . north of Kudligi town the great run which com- 



Niddagurti hill run. & & 



mences in the Niddagurti hill forms a consider- 



1 Siddapan Konda, a very bold peak, rising 2,151 feet above sea-level, is the 

 highest point in the district east of the Haggari river. 



( 175 ) 



