136 GEOLOGY OF TEICIIIXOPOLY,, &C. [ClIAP. VI. 



lagoons connected witli the sea^ as those of Mercanum or the Chilka 

 and Pulicat lakes,, it is evident that the whole of the low country 

 of our area must have been under the waters of the sea in question, 

 oiit of which the Shevaroys and other mountain ranges would alone 

 have risen as islands. No indications remain of such a state of 

 things, and there is good reason for believing that no such great 

 depression of the metamorphic country has taken place since it ac- 

 quired its present general contour. If such a sea ever did surround 

 the mountains and highlands, it must have been at a period subse- 

 quent to the formation of the Cuddalore sandstone series ; unless we 

 presume the regur to belong to more than one geological pei-iod, — a 

 presumption not warranted by our present knowledge of the facts con- 

 nected with the several formations of Cotton-soil before enumerated. 

 Supposing such a sea to have existed, the question at once presents itself, 

 what has become of the sedimentary deposits, both littoral and pelagic, 

 formed by it ? We can hardly suppose that they would all be so utterly 

 swept away by denudation as not to have left any traces whatever among 

 the numerous and often very tortuous valleys of the mountain country. 

 We cannot, then, attribute the formation of the Darmahpoor Cotton-soil 

 to the action of brackish water lagoons connected with a sea washing over 

 o-reat part of what now forms the Baramahal, but must suppose the regur 

 to have been deposited in shallow fresh water lakes, or, if the water was not 

 fresh the saline properties must have been derived from the decomposi- 

 tion of the metamorphic rocks of the neighbourhood in which the deposit 

 took place. The same argument will apply to the other high level regur 

 deposits of the Earamahal, and also to those in the neighbourhood 

 of Salem, but not so forcibly 'to those occupying lower levels nearer the 

 coast. 



The position of the cotton-soil spreads which we have enumerated, 

 in so far as they are comparatively elevated, would seem to indicate 

 shallows in the then inundated country, which would be the sites of 

 vegetable life, while the adjoining spreads of davlv coloured calcareous soil 



( 35S ) 



