246 KING: KADAPAH AND KARNÜL FORMATIONS. [PART IIT. 
been an axis of flexure between these two points, or a system of faulting by 
which the lower quartzites and slates were brought within the influence of 
denudation. Mr. Foote's north-north-west line of fault, were it continu- 
ous into the Yellaconda, would strike this area of alteration in dip, and the 
region of disturbance in the quartzites, at the south end of Unkalumma. 
It is unfortunate that these lines of disturbance, if they exist, 
are not clearly displayed; and it is far-fetched to try and bring in a 
series of displacements on such poor grounds as are given above; but 
the point still remains for solution, viz., that in such a short distance, 
there is the remarkable change from a series of quartzites overlying slates 
to rocks of a like kind underlying slates which to all appearance belong 
to the same series. A system of faults equivalent to a throw of perhaps 
1,000 feet 1s the result of one view, while a tremendous inversion along 
an axis of flexure of ten miles 1s required for the other. 
The stratigraphy of the whole field points as clearly to the south 
part of the Yellaconda, with the exception of that south of the 
Venkatigherry pass,* being made up of quartzites belonging to the 
group at present under consideration, as it does to the northern or 
Cumbum part of the range being altogether a lower series of quartzites. 
May not, therefore, these indications of a system of faulting in this region 
be taken as part of the reasoning in favour of the same conclusion? 
On the south-western flank of the Byrenconda, the Cumbum slates 
Nemillygoondum quart- are overlaid by a series of white quartzites which 
s show strongly to the westward on the Poppanain- 
pully plateau and again further to the south in the hill ranges of the 
Nemillygoondum Pagoda and waterfall. 
Here the strata are generally massive white sandstones. Mr. Foote who 
saw most of this part of the field refers to this sub-group as follows :— 
* The quartzites of this formation are very typical, generally of a pale buff-drab 
color, extremely compaet and semi-vitreous, and showing several series of fime joints 
* Taking the synclinal north of Giddaloor as a fair average representation of the 
thinning out of the Cumbum beds.—W. K. 
( 946 ) 
