RECENT DEPOSITS OF NERBUDDA VALLEY. 283 



river may, on the whole, be regarded as absolutely horizontal, the trifl- 

 ing undulations above alluded to, being the result 



Extent of clay. 



of the method of its original deposition rather than 

 of any subsequent elevation or disturbance. 



The lateral extension of this clay in a North and South direction so 

 far as actually seen, is at present inconsiderable. It mostly follows the 

 main trough of the Nerbudda and some of its most important tributaries, 

 though its actual boundary is difficult to determine owing to the fact of 

 its being covered over by the more recent deposits. These are seldom 

 cut through by the minor streams at any distance back from the Ner- 

 budda, and consequently they effectually conceal the bed in question, 

 but there is little reason to doubt that formerly, along with the other 

 beds of the group, it filled up the* entire level portion of what now 

 constitutes the Nerbudda valley. 



The character of this bed is essentially lacustrine, and it was probably 

 deposited at a period when the present valley of the Nerbudda was 

 occupied by a series of lakes connected more or less intimately with each 

 other, and fed by a slowly flowing river down which clayey sediment and 

 occasionally carcases of various animals were carried, and distributed in 

 a gradual and uniform manner over a considerable breadth of country. 



No other supposition seems adequate to account for the uniform 

 appearance and absence of stratification which this clay every where 

 exhibits, though the upper beds, from their coarser character, were 

 accumulated under different conditions and in a more rapid and irre- 

 gular manner. 



Dr. Impey appears to have received the same impression touching 

 the former lacustrine conditions of the Nerbudda valley, for at pao-e 8 

 of his Memoir on the valley, in the Bombay Government Records 

 No. XIV. new series, he thus expresses himself — " The true valley of 

 the Nerbudda may therefore be confined to the undulating districts of 

 the basins which have evidently been marine lakes" 



