392 MK. G. W. LAMPLUGH ON THE 



waj-, similar to that classed as a separate deposit by Messrs. Wood 

 and Home in the Holderness sections under the title of " Hessle 

 Clay " *. Farther north every trace of a dividing line at this horizon 

 disappears. 



On either side of the ridge of Boulder-clay on which the Quay t 

 stands, an extensive series of stratified beds fills the depression in 

 the Boulder-clay surface. On the south side these consist chiefly of 

 ripple-marked sands and warp (" the Hilderthorpe series " t) ; and 

 on the north of well-bedded chalky gravels (" the Sewerby 

 Gravels " §), the latter overspreading most of the sloping ground 

 bordering on the sea between the Quay and Flamborough village (2 h 

 of figs. 3, 4, and 5). These beds seem to be of Glacial age, and 

 have been referred by Mr. S. V. Wood to the agency of waters issuing 

 from the melting ice of the " Hessle-Clay " period ||. I have myself 

 tried to show ^ that they have more probably been deposited by 

 fresh water issuing from the great valley of the Wolds. 



In the lowest ground on either side of the town freshwater marls 

 a few feet in thickness, with layers of peat, make their appearance 

 above the drifts ; but as these should clearly be classed as post- 

 Glacial, I shall not again refer to them. There is evidence, how- 

 ever, that the climate was still much colder than it now is when 

 the deposition of these marls began **. 



(b) Fottej' HiU (PI. XIII. fig. 3). — In the section just described 

 (fig. 2) all the leading features of the Holderness cliffs are more or less 

 distinctly traceable ; but in the mile-long interval between this place 

 and the sudden appearance of the Chalk in the cliff at Sewerby, 

 great changes supervene which completely alter the aspect of the 

 sections. Unfortunately the cliff within this space is nearly always 

 obscured by slips and talus, and it is only within the last two years 

 that the excavations into the bone-yielding beds at Sewerby, and 

 the erosion of the cliff and beach during a winter's storm, have 

 presented a combination of circumstances favourable to the unravel- 

 ling of the section. The chief features as I now read them are 

 embodied in figs. 3 and 4 ft. 



The Basement Clay does not die out, as had been supposed, 

 against the rising slope of the Chalk, but after continuing for half a 

 mile on the foreshore between tide-marks, rises again into the cliff* 



* Quart. Journ. Geol. See. vol. xxiv. (1868) p. 146. 



t Local abbreviation for ' Bridlington Quay.' 



\ ' Glacial Sections,' pt. ii. sujjra cit. ; also J. Phillips, ' Geol. of Yorks.' pt. i. 

 3rd ed. p. 82; and H. C. Sorby, West-Eiding Geol. & Polytechn. Soc. vol. iii. 

 (1852) p. 220. 



I J. R, Dakyns, ' Glacial Beds at Bridlington,' Proc. Yoi'ks. Geol. & Poly- 

 techn. Soc. vol. vii. (1879) p. 124. 



II ' The Newer Pliocene Period in England,' part ii., Quart. Journ. Geol. Soc. 

 vol. xxxviii. (1882) p. 716. 



^ * Glacial Sections.' pt. iii. sicpra cit. p. 252. 



** Dr. Natlior.st ' Ueber neue Funde von fossilen Glacialpflanzen,' Engler's 

 botan. Jahrbucb, (1881) p. 431, and Mr. Clement Eeid's Holderness Memoir, 

 p. 78. 



ii" See also ' Glacial Sections,' part iv. supra cit., and .section in ' Explications 

 des Excursions,' Internat. Geol. Congress, (18S8) p. 165. 



