PHYSICAL GEOLOGY. 7 



The geological survey, as already stated, was conducted for the most 

 part by the late Charles M. Oldham, then Deputy 



Work of survey. . r J 



Superintendent, and by the writer, but certain 



parts of the country were revisited in later years by Mr. K. Bruce Foote 



mainly in connection with his examination of the extension of the 



Rajmahal plant shales. 



CHAPTER II.— PHYSICAL GEOLOGY. 



The form of the country, within the limits laid down, is very simple, 



Table of rock forma- being a wide uneven plain, having the sea along 



ons ' one of its edges and a mountain wall on the other ; 



but it is so intimately connected in its origin with the physical structure 



of the adjacent country, that important questions regarding the southern 



portion of peninsular India may to a certain extent be touched on in 



describing it, and for the readier comprehension of this treatment of the 



physical history, the following list of the geological formations or groups 



is now given, even though there must necessarily be some repetition in 



the more detailed discussion of them in their proper chapter : — 



Local Geoups. Indian Equivalents. European Equivalents. 



g. Blown sands. ... "\ 



f. Alluvial deposits (River > Recent and sub-recent. 



and Backwater). J 



e. Lateritic conglomerates and Lateritic deposits (R. B. Post-teetiaey. 



breccias, Gravels, Talus Foote). 



debris, 



d. Laterite and Ferruginous Cuddalore sandstones. ... ? Middle Eocene. 



c. Plant shales. ... "Rajmahal beds. ... JUEASSIC. 



b. Quartzites and Clay-slates. Cuddapah Seeies. ... ? Lowee Paleozoic. 



a. Gneisses of various kinds. Gneiss, 



Granites and traps asso- 

 ciated with (a) and (b). 



The southern portion of the Peninsula is distinguished by a great 



Marked features of low and well-known physical feature, namely, the 



country and ghat step. arrangement of the land surface as a coastal plain 



or the low country, with a more or less distinct step or ghat edging an 



( US ) 



