296 



GEOLOGICAL SURVEY 



Oldham and the writer on the tracts they surveyed were 

 embodied in Mr. King's memoir which was published in 1872. 



The lower or Kadapa group was divided by Mr. King 

 into four group's, called after the rivers along which or the 

 mountain group in which they occur. These are : — 



Krishna group, 

 NaHamalla group, 

 Chej^er group, 

 Papagni group, 



each of which is again sub- divided into different sets of 

 quartzites and slates. Limestones are not unknown in the 

 Kadapa rocks associated with the slate series, but are local 

 in their distribution. They are most largely developed in 

 the lower part of the formation in the Vaimpully sub- 

 division of the Papagni group, and are associated with 

 slates and intrusive sheets of trap. These limestones are 

 frequently serpentinous. The base of the lowest quartzites, the 

 Grulcheru beds of Mr. King, is in parts very coarsely conglo- 

 meratic. The western side of the Kadapa basin shows 

 but trifling disturbance since its deposition, but the eastern 

 side along great part of the Vellakonda Range (the Nellore 

 Section of the Eastern G-hats), the rocks, chiefly quartzites of 

 great thickness, have been tremendously affected by vast 

 lateral pressure and crumpled into great folds, some of which 

 appear to have become inverted. Great faulting has also 

 taken place, and for many miles together the boundary 

 between the gneiss and Kadapa rocks is a great line of 

 fault marking a great upthrow on the eastern side. The 

 great contortions of the quartzite beds and the lofty mural 

 scarps they show in many places give rise to much fine 

 mountain scenery along this part of the Eastern Ghats. Much 

 very fine scenery is afforded also by the tremendous quart- 

 zite scarps of the (Naggery) Nagari mountains and the Tri- 

 petti mountains, the southern outliers and the southern 



