Chap. 12.] w. blanford, western india. 71 



Alluvium of Guzerat. As already mentioned^ this is similar in its 

 Similar to aUuvium of ™^^^ features to the alluvium forming the plains of 

 river plains. ^j^g ^^^^ valleys. Like them it consists of brown 



clay, containing kunlmr above, and of conglomerates, gravels and sands 

 below. The streams cut deep ravines through it, and it forms cliffs of 

 some height along their banks. Its surface is frequently, as near Broach, 

 perfectly horizontal over large surfaces, at other times slightly imdulatino- 

 in consequence of inundation. 



It is by no means clear by what process this alluvial deposit has 



^ . . , been formed. It is very similar to that seen alono" 



Ongm obscure. ^ 



a large portion of the Indian coast, and which is 

 usually supposed to have been recovered from the sea by a slow process of 

 upheaval. But how this has taken place is not so evident. Along the sea 

 itself, where raised coast lines are constantly met with, they usually 

 consist of blown sand-hills, and similar hills fringe the present shore; 

 so fine a sediment as that which has formed the fertile plain of Guzerat 

 is deposited in comparatively deep water at a distance from the breakers. 

 During slow emergence from the sea the upper portion of the clay would 

 be mixed with and covered by sand. But the reverse is the case, the 

 sand is covered by clay, and.it is therefore more probable that the latter 

 is a river deposit. In favor of this is the fact that wherever shells have 

 been seen associated with it they are of fluviatUe species, but they have 

 only been noticed at a considerable distance up the rivers and near the 

 hill country. 



It is possible, and even probable, that the clays of Guzerat may have, 

 to a considerable extent, accumulated in * backwaters,'' that is, in coast 

 lagoons. Still it does not seem likely that these could have covered the 

 whole surface, and the uniformity of the deposit is remarkable. The car- 

 bonate of lime now existing as kunkur may have been originally derived 

 from shells as has fi-equently been suggested before. One peculiar eii'- 

 cumstance in connection with these deposits was noted on the Nerbudda 



( 233 ) 



