1868.] JUDD 8PEET0N CLAY. 2'^^ 



" Speeton Gap,'' we find a lower range of cliffs of clay much tumbled 

 and broken, and sending out long promontories or spurs, which reach 

 the high-water mark. This clay cliff-range extends in length about 

 1000 yards, and varies in height from 150 to 220 feet. It is 

 divided by projecting spurs into three well-marked portions, which 

 are known by the names* of Black Cliff, Middle Cliff, and New 

 Closes Cliff. The southern portion of the range is almost free from 

 drift ; but in going northwards beds of Boulder-clay and contorted 

 drift are found to descend and occupy more and more of its face, 

 until, at the northern extremity of the New Closes Cliff, they reach 

 the level of the sea. North of this point the cliffs of Filey Bay are 

 almost entirely composed of drift ; and it is only at a few spots that, 

 by the aid of landslips in the cliffs, by scars exposed at low-water, 

 or by the occasional scouring of the beach during heavy storms, 

 the subjacent rocks are exposed. At Filey Brigg the lowest beds of 

 the Coral Rag and those of the Lower Calcareous Grit rise above the 

 level of the sea, and are seen beneath the Boulder-clay. 



The beds of the Speeton Clay are quite unconformable with those 

 of the Chalk and Hunstanton limestone which lie upon them. 

 While the latter strata have but a very slight dip (amounting, ac- 

 cording to Young and Birdf, only to about 100 feet per mile, or even 

 less), the clays, as seen in the cliff, have an apparent dip of about 

 7°; the true dip, however, does not coincide with that of the 

 section, its real direction being S.W., and its amount 10°. The 

 strata at this part of the Yorkshire coast exhibit signs of great dis- 

 turbance : while in some places they lie very evenly, in others they 

 are thrown into great undulations. Professor Sedgwick J, in 1826, 

 called attention to the fact that the beds of chalk as seen in the cliff 

 between Speeton Gap and Flamborough Head are violently contorted ; 

 and a similar phenomenon is exhibited in the Hunmanby cutting of 

 the Hull and Scarborough Railway. The clay beds of the New 

 Closes Cliff are likewise contorted ; at the time of the publication of 

 * The Geology of Yorkshire ' these contortions were manifest to a 

 spectator looking at the cliff; and Professor Phillips has given a 

 diagram § of them drawn to scale, which diagram is rendered of 

 greater value by the fact that the mining operations for procuring 

 phosphatic nodules have now entirely concealed the face of this part 

 of the cliff. Any one, however, who will take the trouble to go 

 through the workings may easily satisfy himself concerning the 

 highly disturbed positions of the beds in this place. I shall show in 

 the sequel that these undulations of the strata extend for at least a 

 mile north of this spot. Lastly, the beds of Coralline Oolite which 

 form Filey Brigg exhibit similar, though less violent, contortions. 



Professor Sedgwick describes j| a, fault as occurring at the junction 



* To obviate the difficulty arising from the usual confusion in local nomen- 

 clature, I have throughout the present paper used the names printed on the six- 

 inch Ordnance map of this district. 



t Survey of Yorkshire Coast, p. 51 (2nd ed., 1828). 



+ Annals of Philosophy, vol. xi. (1826) p. 342. 



§ Geology of Yorkshire, pi. 8. jj Ann. of Phil. vol. xi. (1826) p. 343. 



