538 O. W. Lamplugh — The Bridlington Shell-bed, etc. 



Over this were sand and clay, and occasionally pure decomposed 

 chalk, and then a mass of Bonlder-clay of the usual description." 



" The lower part of the section is much contorted, in the manner so 

 common in the drift strata, as described by me in my paper on that 

 subject, and there attributed to the action of icebergs. It is also 

 well worthy of remark that the same force which produced these 

 contortions appears to have fractured some of the shells imbedded in 

 the clay, and displaced the fragments, which, nevertheless, may often 

 be found within a short distance from each other. I have in my 

 collection a number of specimens of Saxicava rugosa that show this 

 fact to great advantage. Indeed, it seemed as though the exposed 

 crag was only the upper portion of the contortions, and that the 

 main bed was below the level of the beach, and might not have been 

 exposed in the cliff if it had not been thus bent and raised up by 

 lateral pressure." 



So far as I know, these are the only descriptions given by eye- 

 witnesses. It will be seen that all agree that the shells occurred in 

 clay as well as in sand, and that the beds were fragmentary and 

 showed many signs of pressure and disturbance. Yet, misled 

 doubtless by the sandy matrix of most of the shells, and by the 

 perfect condition of those which were collected, — for in a mass like 

 this the best specimens would naturally be selected, — most geologists 

 now seem to regard the bed as a seam of undisturbed sand 

 with shells, in place. 



Thus Messrs. Wood and Eome ' describe the shells as occurring 

 in a bed of sand in the lower part of the Purple Clay, and Sir C 

 Lyell in his ' Student's Elements'^ refers to it as "a thin bed of 

 sand resting on glacial clay with much chalk debris." 



Three years ago, Mr. Bed well and myself^ were able to prove, 

 by fragmentary shells collected from the Basement Clay, and by its 

 position on the beach, that the shell-bed was in this division, and 

 not in the Purple Clay ; which I am now able to confirm by direct 

 evidence. 



In his latest paper* Mr. S. V. Wood says of the bed — "The 

 Bridlington shells unquestionably lived where they occur, for they 

 are in the most perfect preservation ; and though the sand con- 

 taining them has, in the specimens I possess, hardened to the 

 condition of rock, the bivalves have both valves adherent and are 

 quite unworn." I think the above-quoted extracts alone are sufficient 

 to show that this conclusion is, to say the least, very doubtful. 



Lists of the Bridlington shells have been published by Dr. S. P. 

 Woodward,* Mr. S. V". Wood, jun.,^ and Dr. J. Gwyn Jeffreys^ 

 (see Appendix A). 



The Dimlington Shell-bed. — Some years ago a similar shell- 



1 Quart. Journ. Geol. Soc. vol. xxiv. p. 149. 



2 Student's Elements, 2nd ed. p. 169. 



3 Geol. Mag. Dec. II. Yol. V. p. 609. 



* Quart. Journ. Geol. Soc. vol. xxxvi. p. 616. 



5 Geol. Mag. Vol. I. p. 49. 



6 Quart. Journ. Geol. Soc. vol. xxvi. p. 92. 



' PhiUips' Geol. of Yorkshire, 3rd ed. p. 274. 



