CHAP. 3.] KADAPAH FORMATION.—CHEY-AIR BEDS. 209 
The metamorphism to which these rocks were subsequently exposed 
may, on the other hand, have had some influence in obliterating any 
effects which the forces necessary to carry this debris might have 
produced. 
Again, the source of the debris may have been calcareous muds 
which were deposited in very shallow water, not far from the localities 
in which we now find the breccia layers; these became sun-dried, as 
we see the thick alluvial deposits in rivers* and tanks of India now-a-days, 
and thus broken up into fragments which were eventually carried off 
by the next floods. There are, at the present time, examples of this 
breaking up of calcareous mudstones in the course of the Khoond-air river. 
Some of the Nundial shales over which it flows, particularly about the 
course between Cuddapah and Chagulmurry, are perfect mudstones, as 
recent-looking as any hardened mud deposits formed at the present time 
in the same river. These become cracked up by exposure, and if not 
carried away, the fragments are at every fresh covered up by a more or 
less red caleareous mud, which is derived from the beds of the very same 
rocks. Were these examples sufficiently extensive, or allowed to remain, 
instead of being annually washed away, there would then be a calcareous 
breccia not at all unlike those of the lower part of the Poolumpett 
slates. 
The next peculiar variety of limestone in the Poolumpett beds is a 
very hard, dark grey and weathering nearly black, 
Se s silieious rock, which often in its appearance and 
mode of occurrence looks like an intrusive igneous rock! The irregularly 
* Along the banks of the Kistnah river there are numerous deposits of alluvium 
left every year for some distance up the tributaries, and these when sun-dried break up 
into great fragmentis two or three feet in diameter.—W. K. 
+ Mr. Charles Oldham was equally struck with me, years before I had an opportunity 
of close examination, by this strange aspect of an otherwise aqueous rock. He says, 
referring to this variety of the limestones near Nundaloor: “The blue impure silicious 
limestone which forms a considerable part of the low hills north-east of Nundaloor 
has very much the appearance, which I have noticed in the same beds elsewhere, of having 
been forced up among the slates.” 
20. € 1209.) 
