136 KING: KADAPAH AND KARNUL FORMATIONS. [PART III, 
are more or less cleaved into slates, this structure being strongest along 
the base of the Nullamullays, where also there is much disturbance 
evident in the quartzites, limestones, &c., of the older rocks. 
One of the most marked characteristics of this formation is the 
prevalence of cleavage throughout the greater 
General character slaty: tent of the rocks. This structure is naturally 
best seen in the clay slates; it is next best exhibited in some of the 
limestones, and least in the quartzites. 
The strike of the planes of cleavage is very constant in its direction, 
seldom varying more than a few degrees, and it generally runs N. 3° W., 
N. 10? W., or N. 15° W., though oftener N. 10 W, In the north- 
eastern on Markapoor part of the country, the direction becomes east 
of north, until in the Palnád, it is nearly north-east—south-west.* The 
dip of the planes is generally to the eastward at 30° or 60°; occasionally 
it is vertical, and very rarely it is to the westward. These planes are 
often curved or slightly undulating, the interstitial partings having 
been subsequently, in many instances, filled in with quartz; while 
the slates are very taleose and chloritic. 
The followmg figures and observations are illustrative of this. 
Fig. 18a is of a section occurring on the eastern flanks of the 
Nullamullays, north-west of Sevashettypully, among dark green and 
rusty brown taleose and chloritic slates, which are curved in their 
bedding and highly impregnated with quartz in the planes of cleavage. 
The letters (a, ره‎ a) indicate edges of stratification nearly obliterated ; 
(b,b, à) edges of undulating cleavage planes showing the interstitial 
quartz. Again, west of the above-mentioned village, there are light 
grey slates much impregnated with quartz. Ordinarily the cleavage 
is N. 5° W., dip 30° to 40° eastwards; but as soon as undulating 
* In this there is a remarkable parallelism with the average strike of the strata. 
( 136 ) 
