CHAP. 5. ] KADAPAH FORMATION.—KISTNAH BEDS. 247 
by which the beds are broken up, so that where exposed in cliffs they often resemble 
gigantic cyclopean walls. This quartzite formation occupies a considerable area in 
two principal localities on the eastern side of the Nullamullays, and forms apparently 
also the narrow central quartzite plateau of these mountains. There is an interesting 
outlier of quartzite forming a ridge immediately east of the large village of Giddaloor, 
which quartzite seems to belong to this group rather than to the next underlying one 
(Byrenconda Quartzites). The lithological character of the Nemillygoondum group 
is, on the whole, very constant throughout.” 
“In the Nemillygoondum section the quartzite occurs in massive beds from 
three to six feet in thickness, nine or ten of which are exposed in the cliff over 
which the Guntacummum river falls. These beds are here bent into a huge synclinal 
fold, out of which the overlying slates have been eroded, together with two or more 
of the top beds of the quartzites.” 
“The thickness of the quartzites (in the foregoing section) is apparently very 
much less than in the section seen in the very picturesque rocky coombe south-west of 
Poppanainpully, in the Bolapilly valley, where the east side of the northern plateau 
is well exposed. In this section the quartzites cannot be less than from 300 to 400 feet 
in thickness.” 
“Towards the north-eastern edge of the plateau, the quartzite is much cut up 
by cleavage planes, running north 5°—10° east, with a very high dip to the east, 
almost vertical in fact. By this cleavage the structure of the rock has been 
completely altered ; the fracture has become slaty ; a laminar structure parallel with the 
planes of cleavage has been set up; and the influence of weathering on the surface 
has been far greater than where no slaty cleavage has affected the quartzites. This 
cleavage but rarely shows in the compact, semi-vitreous, pure quartzites: indeed in 
most cases where quartzite is thus cleaved, numerous tiny plates of silvery grey mica 
are to be detected in its substance.” 
“ The outlier of these quartzites above referred to, lying to the east of Giddaloor, 
forms a narrow elevated shallow synclinal trough; whatever 
previously overlaid the quartzites having been denuded 
away. At the southern end the structure of the hill is extremely obscure, for although 
of a very hard massive variety of rock, it has been so much affected by cleavage that 
the bedding is not at all satisfactorily traceable. There are indications of the synclinal 
fold on the summit of the ridge. Further north, where the ridge widens out, the 
synclinal structure becomes more evident, and is quite distinct near this end of the 
outlier. The rock is exactly like that of the Nemillygoondum beds.” 
Giddaloor outlier. 
On the Nundycunnama and above Howhoblum, the Tepresenta- 
Nundyeunnama and tives of the Nemillygoondum quartzites are very 
Howhoblum. 
much as Mr. Foote has described above, viz., very 
(1247) 
