CHAP. 4.] KADAPAH FORMATION.—NULLAMULLAY BEDS. 225 
reached the curved character is almost obliterated by the denudation of the south 
side of the anticlinal having been greater than of the north ( Fig. 39). 
Fig. 39. Section at Peddakoo hill. 
* À change in the lithological character of the beds has been gradually taking 
place from the northward of the Junna Cunnama, many of the quartzite beds having 
assumed a markedly micaceous character which seems to be increasingly deve- 
loped eastward of the Vamalapaud pass. Some of the beds are so micaceous as 
almost to pass into a mica schist. Some of these are to be seen near the Nellore end 
of the pass about half a mile north-east from the foot. Like the typical semi- 
vitreous varieties these micaceous beds are almost invariably of pale color; either pale 
pink, white, grey, bluish or greenish. 
“The bottom bed of the KADAPAH ROCKS in this part is of a mixed character, 
partly semi-vitreous and pure; partly also rather micaceous ;* it is well exposed on the 
flanks and summit of the Lingumcoontla spur of the Peddakoo hill. The unconform- 
ity of this quartzite to the underlying gneiss and mica-schist is very marked, although 
in some places an apparent conformity has been caused by the extensive and 
complicated crumpling of the quartzite bed.” 
The Cumbum tank-ridge of DN Ml quartzites, both flagg 
and thick beds, is traceable continuously ee 
Byrenconda outcrop i 3 i 
towards Muntaral Cun- wards to Tirmaldaverconda beyond the Tiggle-air, 
nama. 
when the inclination of the beds becomes suddenly 
lower, and there is a twist round of the strata to the westward. 
Tirmaldaverconda is found to be capped by these beds, and west of that 
all recognition of a separate band of quartzites is lost in the superficial 
+ Fhis bed, if really belonging to the Byrenconda group, would by its position indicate an 
overlapping of the lower beds by that group. Such an overlap may really exist, but it is also quite possible 
that the bed in question may represent the true base of the KADAPAH rocks, in which cease the equivalent 
of the four remaining sub-groups would have to be fixed among the overlying beds near the base of 
the Peddakoo section. Ip the latter case a great lateral change of mineral characters and also a great 
thinning out of all the beds must have taken place, as compared with their vertical extent and litholo- 
gical peculiarities in the typical region north-east of the Byrenconda.—R. B. F. 
2 E ( 335 ) 
