66 KING: KADAPAH AND KARNÜL FORMATIONS. [PART It. 
geology of the area of denudation south of the wall most interesting and rather com- 
plicated. Of the pinnacled quartzite only two outliers remain, one about two and a half 
miles east of the large village of Calwa; it is of small extent only, but important and cons- 
picuous, because perched on the top of a short flat-topped ridge rising nearly 300 feet 
above the valley. The top is capped with the quartzites, and distinguished by several 
fine specimens of pinnacle ‘tors’. This capping rests upon a great thickness of 
* Owk shales,” and the east end of the ridge offers a capital section of these, underlying 
rocks. This small outlier at once explains the formation of the quartzite wall. The 
wall, for that is the best name descriptive of the long narrow line of outcrop of the 
quartzite, measures about 13 miles from Chennagapilly, westward to its junction with 
the Chintalpilly plateau. Throughout this whole distance it retains its character of 
an independent ridge wall, except for about half a mile along the base of the Gooman- 
conda, where it leans against the hill. 
= “ The northward dip of this great basset edge or outcrop is generally very high 
indeed, varying from 60° to 80°. Except in one place a little south-west of Calwa the 
top of the ridge is extremely narrow, often not more than 20 to 30 feet. But near Calwa 
the bed makes a double dip, as shown below in section, owing to less complete 
Fig. 8. Sketch-section near Calwa. 
denudation for a distance of three or four hundred yards, to the south of 
Bapunpilly, where the wall-like character of the quartzite outcrop is extremely well de- 
veloped; this bed rises in cliffs, but little short of a hundred feet high above the valley 
. of the Khoond-air. At foot of the quartzite wall, the Koilkoontla limestone appears 
in very many places dipping north at an equally high angle; but as it is followed 
in to the plain the dip rapidly decreases, and before it crosses the bed of the Khoond-air, 
the beds approach very nearly to horizontality. The quartzite is throughout the 
length of the outcrop very white in color, and differs only from the less disturbed 
portions of the formation in being less. distinctly laminar,—a change of character 
which may have been brought about by the enormous pressure and consequent heat 
during the process of dislocation at that very part of the originally undisturbed bed. 
The mass of the rock in the wall is much more broken up by irregular fissures than 
where inclined at a low angle,” 
Oe 1) 
