OHAP. 3.| KADAPAH FORMATION.—CHEY-AIR BEDS. 207 
We could not, however, certainly recognize those slates; all the different 
bands which appear on this part of the range being much undulated 
and altogether more schistose than any of the beds in the flat valleys 
to the westward. 
The dome-shaped arrangement of the Koyamon Conda was to 
NR NO some extent eut off by faulting, for, as will be 
seen on the map, the gneiss occurs right up 
against the quartzite of the eastern base of the ridge. 
The various bands of limestone are generally more or less silicious 
as also magnesian, and to some slight extent are of grey colors, though 
there are exceptions to both these characters; 
as on the north or left bank of the Chey-air, 
where they are often red and purple earthy limestones, with thin compact 
Character of limestones. 
and grey beds, lighter-colored than generally occur to the south. We 
did not observe any traces in the Chey-air basin of those oolitoid 
silicious bands which are so common in the Vaimpullys, and which at 
first sight might be taken as the northerly extension of this sub-group. 
The outcrop of Poolumpett slates in the western slopes of the 
range of hills enclosing the western side of the Ontimitta valley, are 
principally red earthy and sandy deposits, with, towards the Cuddapah 
end, a good thickness of purple clay-slates. The limestone bands in 
this outcrop are very thin, and finally disappear almost entirely in the 
western slopes of the Polleonda. "The band is comparatively thin here, 
and shows very well above the flat terrace overlooking the famous 
Pedda Gaudee cataract* south-south-east of Cuddapah town. 
In the western slopes of the Polleonda the outcrop of the Poolum- 
pett beds is completely discontinuous with its representatives further 
westward in the Tadapurtee valley; but when these are reached, 
there is the same thin outcrop of pale red earthy and sandy beds with 
* A wild and picturesque rift cut by the Boogoo river in the vertical cliffs of a great 
bay which has here been denuded in the lower quartzites of the Chey-air series. 
( 207 ( 
