192 
[vOL. XII. 
Records of the Geological Survey of India. 
Javacli mountains, are great bands of granitoid gneiss, some of them remarkable 
for their coarseness of texture, -which is blotchy and often markedly porphyritic, 
e. g., the rock forming the mass of the Palikonda (Policondah) mountain and of 
the Vaniambiidi* trigonometrical station hill, some three or four miles to the south- 
south-east. Similar “blotchy” gneiss is of very common occurrence elsewhere. 
In the Palikonda hill the rock is of a hornblendic variety, and of grey color. 
A remarkably handsome vaiioty of porphyritic hornblendic granite gneiss of 
rich green and pink colors occurs at the western base of the Nagari (Kaggery) 
Nose mountain, and is exposed in several cuttings along the Madras railway 
(north'-west line). Masses and boulders of this variety are to be seen included 
in large number’s in the basement conglomerate of the Upper Goudwana rocks in 
the Pyanur area south of the Nagari river. 
The contrast between the rich dark-green hornblendic matrix and the large 
pink or salmon-colored crystals of orthoclaso makes the rock a very handsome 
example of a typical porpbyi’itic granite gneiss. 
A by no means uncommon fo»’m of the granite gneiss is one in which the beds 
Quasi “ breociated ” include masses of what apf)ears to be an older gneiss, 
gneisa. sometimes micaceous, sometimes hornblendic. The in¬ 
cluded masses present generally sub-angular forms, but others are well rounded, 
as if they had been boulders, and others again unquestionably angular, so that 
the mass looks sometimes conglomeratic, sometimes breccioid. In other places 
again, and often within the same beds and at no great distance, the inclusions have 
the .appearance of having been altered by concretionary segregation. The in¬ 
cluded masses are mostly of finer gi-ain and of more highly micaceous or horn¬ 
blendic character than the surrounding masses. There can be little doubt that 
in some cases the included fragments arc really remains of older rocks, and the 
whole rock a true breccia or conglomerate. In other cases, however, the inclusions 
are in all probability more local aggregations of the prevalent or most striking 
mineral. An example of this latter kind is to be seen in the Chikeli Drug hill, 
a little to the south-east of Kaneambadi pass, nine miles south of Vellore. Good 
examples of this quasi-conglomeratic and brecciatod structure may be seen to the 
west of the Nagari railway station, in the low hills close to the railway at Ra- 
nawaram near the Sholinghur station, and in the southern part of the district at 
and to the south of Chitpat (Chittapett), .and at Erumbaucum, eight miles to the 
east-south-east of Arcot, and on the eastern side of the district at Gudinaucarur, 
six or eight miles east of Wandiwash. 
Of the more schistose bands of gneiss, the most noteworthy is the great 
Schistose band of Kai- micaceous band forming the Kailasagiri peak, six miles 
lasagh’i. south-west-by-south of Vollore, which rises in a bold peak 
to an elevation of 2,677 feet above sea level. This gneiss is compact and massive 
in structure, and has been uptiltcd to a very high angle, the ti-uo dip of the beds 
varying from 80° to 85°. The strike of the beds corresponds with the direction 
of the highest part of the ridge and is north 5° east. 
The very coarse garnetiforous micaceous gneiss of Chikeli Drug (already 
' Tins iTJXist not be confonndetl with the town and railway station of the same name on 
the northern boundary of Salem district. 
