542 G. W. Laniplugh — The Bridlington Shell-bed, etc. 



covery of an outlier of the Basement-clay, between tide-marks in 

 Filey Bay opposite the village of Keighton ; and there, too, it con- 

 tained the same clay-streaks with crushed shells, — chiefly Cardita 

 horealis. 



These three are the only places where I have as yet seen this 

 blue ' Basement ' Boulder-clay, and the shell-streaks therefore seem 

 to characterize it. 



Stratigraphical Eelations or the Shelly Boulder-clay. — 

 Though I have throughout called this shelly Boulder-clay the 

 'Basement Clay,' to describe its position in the series, it is not, 

 perhaps, quite correct to do so, as Messrs. Wood and Eome, who 

 established this division, trace it in many places where the shelly 

 clay does not exist, making it extend along the base of the cliff 

 from Dimlington northwards to beyond Hornsea.^ These gentlemen 

 have, I think, included in their division a hard massive Boulder- 

 clay, greyish in colour and very full of chalk, which overlies the 

 shelly clay on both north and south sides of Dimlington Heights ; 

 but it is somewhat irregular and intermittent under Dimlington, 

 having apparently suffered severe erosion. Shells, even in frag- 

 ments, are very rare in it, — rarer even than in the overlying 

 Purple Clay. 



This chalky clay is, I think, more closely connected with the 

 ' Purple ' than with the shelly clay ; but should it eventually be 

 retained as the top of the ' Basement Clay,' the shelly clay must be 

 described as a zone in that division. 



Above the chalky clay at Dimlington there are in places twenty 

 feet of bedded sands and fine clays with no fossils, and then the 

 Purple Clay, often in two divisions. 



At Bridlington, the shelly clay, wherever it comes below beach- 

 level, is overlaid by a finely laminated and in places ripple-marked 

 clay of a deep brown colour, — very tough and unctuous, — containing 

 no stones, and varying from two to sixteen feet in thickness, as it 

 fills and levels hollows in the lower clay ; but as soon as the top of 

 that clay rises above the beach-line, the laminated clay disappears, 

 and the Purple and Shelly Clays come together as in the section 

 under the Alexandra. 



This is probably owing to erosion during the formation of the 

 Purple Clay, as, in the section just referred to, masses and bauds of 

 the lower clay were seen twisted upwards for some distance into 

 the Purple Clay (at B), just as the Purple Clay into the gravels a 

 little further north ; and there were also one or two detached patches 

 of laminated clay agreeing in appearance with this bed in the lower 

 part of the Purple Clay (at C). I obtained another proof of the 

 later disturbance which the whole mass of the lower clay must have 

 suffered : for in it, under the Alexandra, one of the many stones 

 with Pholas borings — a hard calcareous nodule which still held the 

 hardened green sand in the holes, and had been afterwards striated — 

 had been broken in two as it lay deep in the clay, and the parts 



^ Quart. Journ. Geol. Soc. vol. xxiv. p. 148. 



