76 



S. V. WOOD, J TIN., AND F. W. HARMER ON THE 



signs of any gradual disappearance of the shells by the abstracting 

 agency being apparent, and also that the dividing line was very 

 irregular, the shelly crag often rising in a boss or prominence (as in 

 sections I. and II.). The unfossiliferous layers underlying in some 

 cases detached portions of shelly material, as in section III., also pre- 

 sented a difficulty. In addition to these was the presence not merely 

 of a separate and independent stratification, but the circumstance of 

 bands of ferruginous loam at the base of the sands, sometimes, as in 

 section II., enwrapping in an entirely unconformable way pro- 

 minences of shelly crag. 



Fig. 2. /Section II, in a pit three furlongs east of Great Bealinys 



church. (Scale 10 feet to the inch.) 



a and b as in fig. 1. 



b\ Band of dark, partly indurated, ferruginous loam. 



Notwithstanding these difficulties, however, we are inclined to 

 think that the view expressed by Mr. Whitaker is correct ; and we 

 have been principally led to that conclusion by the detection of the 

 band of pebbles shown in section I., which seems clearly to indicate 

 that the original oblique stratification of the Crag once prevailed 

 through these sands, and that the agent which abstracted the 

 calcareous material was inoperative upon the pebble-band, which 

 remained as part of the original stratification. If this view is 

 correct, it is clear that in many, indeed in most, cases the material 

 has been so far restratified in the process, that the present stratifica- 

 tion of the sands is often as unconnected with the original stratifica- 

 tion of the deposit as is cleavage or jointing in the cases of the old 

 rocks. 



In saying this, however, we would not be misunderstood as 

 suggesting that there has been a rearrangment of the whole of the 

 original material of the Crag, because, since the originally oblique 

 bedding of the pebble-seam remains unaltered, it is evident that the 

 arrangement of the sand particles among which this was imbedded 

 cannot have changed, or the position of the pebble-seam would have 

 changed with them. It is the argillaceous and ferruginous material 

 taken up by the percolating water which has been redeposited, so as 

 to form, in combination, the coloured threads and bands which give 

 rise to this apparently new stratification. 



It not unfrequently happens that the sands and the shelly Crag 



