Natural History. 75 



marine fen silt, in the fens to the east of Lincoln, in the 

 parishes of Branston and Dunston ; and the skull of a Walrus 

 was not long since dug up from the peat near Ely; indicating 

 that this animal formerly inhabited the valley of the Ouse, 

 which, at that time, was probably an estuary. 



To the west also, where the Trent valley lies, it is quite 

 probable that the sea occasionally covered the land in past 

 times before the river was banked ; but this would be only for 

 a time, and during exceptionally high tides ; and when we 

 think how low the land is on that side, and that the aegre, or 

 tidal wave, which runs up the Trent, is felt quite 14 miles 

 above Gainsborough, we cannot wonder at it. 



In addition to this, there are proofs of the near presence of 

 the sea in the finding of recent marine shells inland. Some, 

 Mr. J. D. Carr informs me, were met with in Newland, at 

 the foot of Lincoln Cliff, during some alterations a few years 

 since. They consisted chiefly of Cardlum edule^ ZMytllus edulls^ 

 and Littorina llttorea the common cockle, mussel, and peri- 

 winkle and they were all dwarfed, as is invariably the case 

 when marine molluscs are found living in salt, or estuarine, 

 marshes, with a large admixture of fresh water. Mr. Carr, 

 in writing about them, says they were "involved in a marine 

 peat containing a good many bones, a large number being 

 those of birds ; the peat underlies the whole of Newland, 

 Guildhall Street, and Brayford, and I should think (though I 

 have seen no sections) the east side of the city also ; the whole 

 rests on the Capricornis zone of the Lias." Besides this, the 

 valve of an oyster shell, having the sandy case of a marine 

 annelid attached, mixed with bones of deer and horse, and 

 pieces of wood, was found recently in Mr. Pearson's new 

 brickyard on the Trent bank at Gainsborough, 14 feet 6 

 inches below the surface, in a bed of sand underlying warpy 

 clay ; and, as the worm case is unbroken, and in good 

 preservation, it could not have travelled far, and had probably 

 been cast up by some stronger tidal rush than usual, which 

 burst over and flooded the land. Beyond, however, these 

 temporary occupations and incursions, there is no record of sea 

 action ; and, in forming the contour of the land, its escarp- 

 ments, valleys and plains, the sea took no part. 



Rivers to start the grips, and atmospheric forces to widen 

 them into valleys, is sufficient for it all. We want no other 

 aid. 



Such is the story of the Lincoln Gap ; one of the many 



