134 Mr. CoLEBRooRE on the North-east of Bengal. 



and mixed with gravel. The strata are in general horizontal^ or nearly so. 

 No prevailing dip was perceived ; but contortions of the strata were re- 

 marked^ which rise and fall slightly in different parts of the bank, in both 

 directions, as if deposited over an irregular surface. They are in some places 

 entirely interrupted by banks of indurated clay or loam. These interruptions 

 are of small extent ; and the horizontal strata soon re-appear on either side of 

 them. In general the uppermost layer of clay coincides in a remarkable 

 manner with the height of the river in the rainy season : but in a few in- 

 stances it is continued to the top of the bank or acclivity. The lower clay is 

 in many places divided by alternate layers of sand in a very irregular manner : 

 more than eighty alternate layers have been counted. 



The general appearance of the clitfs shows the following strata in succes- 

 sion, beginning from beneath ; viz. 1st, slate-clay, of the thickness of twelve 

 feet above the lowest level of the river in the dry season : its depth below that 

 level is undetermined ; 2d, ferruginous concretions and indurated sand, to a 

 thickness of from three to eight feet ; 3d, yellow (or rather green) sand, from 

 three to eight feet : 4th, a layer of slate-clay, of little thickness in general, 

 and wanting in many places : it corresponds to the height of the river during 

 floods ; 51 h, sand, with small stones or gravel, from twenty to fifty feet. 



In different parts of the cliff there have been found clay iron-stone, coarse- 

 grained sandstone, iron-stone concretions, nodules of slate-clay and fossil 

 wood. The clay iron-stone occurs in the coarse-grained sandstone, a bed of 

 which of small extent was observed in one place. The nodules are found in 

 a discontinuous but horizontal layer in the stratum of clay; they are compacter 

 lumps of it. Blocks of fossil wood were met with upon the indurated sand, 

 and were thought by Mr. Scott to have fallen from a higher position. They 

 lie upon a ledge of the bank, which, being of firmer texture than the layer of 

 sand above, has better resisted the action of the river encroaching on the 

 banks. Apparently they belonged to an upper and looser portion of the same 

 sandy stratum. 



Mr. Scott likewise found pieces of fossil wood, among shells and other ani- 

 mal exuviae, in a very singular bed of organic remains discovered by him. It 

 is situated under a small hill in the cliff (rising about twenty feet over the gene- 

 ral elevation), and lies about seven feet below the level of the highest flood of 

 the river. Both above and beneath it are layers of clay ; and it rests upon 

 alternate strata of sand and clay. Their extent is small, being interrupted by 

 beds of uniform sand. The spot may be about a hundred and fifty feet, at the 

 most, above the level of the sea. 



Among the organic remains found in this singular assemblage of them, many 



