CHAP. 3.] KADAPAH FORMATION.—CHEY-AIR BEDS. 185 
times three distinct flows of trap, which are again succeeded by the 
different shales, &c., until near the Gundycotta range, when red and pur- 
ple shales come in with bands of thick-bedded quartzites. These are the 
highest beds, and are overlaid by the quartzites of Gundycotta, which 
constitute a new group. 
There are in this succession three classes of rocks to be more 
Three classes of rocks particularly noticed ; the traps and silicio-felspathic 
و‎ beds, the jasper series, the limestones, and the 
shales, which are the dominant deposits. 
The term shales is hardly a correct one, for they are cleaved, some- 
times rather strongly, though they are never so 
Slaty shales. 
close in their character to true slates as those of 
the Nullamullay and Cumbum country yet to be described. It is very 
diffieult at times to distinguish the results of cleavage from those of 
jointing, especially of the north-south system.* Besides, the shales may 
after all be thus jointed to a maximum extent in this direction which is 
very nearly, if not exactly, with the cleavage. Both cleavage and jointing 
have, however, been impressed on these rocks; the latter very strongly. 
It thus happens that these planes, combined with the original tendency to 
separation along laminar surfaces, have produced the peculiar spicular 
form of the disintegrated fragments so peculiar to some of the finer shales. 
The western slopes of the Gundycotta range are often covered with a 
debris of small rudely needle-shaped or spicular fragments of shales.+ 
The force of cleavage was so faint as never to have overcome 
SEES TRES obscured the laminar tendency to separation. 
faint. This last feature is always to be recognized, and is 
always capable of being taken advantage of in the quarrying of the 
* The direction of the joints may vary 10? on either side of this general run. 
T It will be seen further on, that some of the shales in the southern representatives of 
this sub-group weather in the same manner. 
