INTRODUCTION. 3 



3. Ancient Kankar and Gravel, imbedding remains of Mastodon 



(Pliocene). 



4. Silicified wood deposits of Pondicherry and older Laterite. 



5. Fresh-water limestone of Nirmul, Hyderabad and Rajahmundry 



(Eocene). 



Secondary Strata. 



6. Limestone beds of Triehinopoly, Verdachellum and Pondicherry 



(Neocomian or Lower Chalk). 

 ?, S & 9. Diamond Sandstone Group (Carboniferous or Devonian). 



Hypogene Series. 



Volcanic and plutonic rocks. 



Among the plutonic rocks, regarded by Newbold as intrusive 

 into the gneisses and schists, were included the gneissose granites 

 which form conspicuous tors of jointed blocks in the Bellary district 

 and other parts of South India. By the earlier workers on the 

 Geological Survey these rocks were grouped together under the general 

 name of Bundelkhand gneiss, and were regarded as constituents of 

 the gneissic complex more thoroughly metamorphosed than the 

 conspicuously banded forms ; they were consequently regarded as 

 probably the oldest parts of the complex. Similar ideas prevailed 

 elsewhere, in Canada, for instance, where the corresponding massive 

 crystalline rocks were known as the Laurentian division of the 

 basement gneisses. Recently, however, there has been a tendency 

 to revert to the ideas which governed Newbold, and to regard 

 these gneissose granites and many other sections of the crystalline 

 complex as igneous instrusions, sometimes older and sometimes 

 younger than the associated gneisses and schists, being batholiths 

 of granite, syenite, diorite and gabbro rendered gneissose in struc- 

 ture by earth pressures, either during or subsequent to their irrup- 

 tion. (Cf. T. H. Holland, Memoirs, Geological Survey of India, 

 Vol. XXVIII, 1900, 119, 242; Imperial Gazetteer o. India, New 

 Ed., Vol. 1, 1907, 59.) 



Dr. H. J. Carter's 1 summary, which appeared first in 1854 and 

 was afterwards reprinted in 1857, was a very much more ambitious 

 attempt to classify the formations then known in India. Subse- 



1 Summary of the Geology of India, between the Ganges, the Indus and Cape Comorin. 

 Journal, Bombay Brarxh, Royal Asiatic Society, Vol. V, p. 179, 1854. 

 Reprinted with footnotes in " Geological Papers on Wtstern India," p, 028, 1857. 



J*2 



