G. W. Lamplugh — The Yorkshire Boulder-clay. 61 



IV. — On a New Locality for the Arctic Fauna of the "Base- 

 ment " Boulder Clay in Yorkshire. 1 

 By G. "W. Lamplugh. 

 Introduction. 



DURING the course of a systematic investigation of the drifts of 

 Flaraborough Head, I have somewhat unexpectedly come across 

 a fragment of marine Arctic beds enclosed in Boulder-clay, similar 

 to those which form the well-known fossiliferous deposits of Brid- 

 lington and Dimlington ; 2 and as this occurs under very different 

 conditions from those already described, it adds materially to our 

 knowledge of the beds, and illustrates more clearly their origin. 



.The newly-discovered bed lies in the face of the cliff on the east 

 side of a shallow recess in the southern coast-line of Flamborough 

 Head, known as " South Sea Landing." This place is within half 

 a mile of the village of Flamborough, and is about four miles north- 

 east of Bridlington, the latter being the nearest previously known 

 locality for the beds. 



The chalk on both sides of this recess forms vertical cliffs below 

 the drifts, varying from 60 to 80 or more feet in height; but here, 

 having been excavated in pre-Glacial or early Glacial times, it sinks 

 suddenly to the sea-level. 



The hollow thus formed has a breadth of about 300 yards, and is 

 bounded on the west side by an abrupt cliff of chalk. On the east 

 side the surface of the chalk shows a more gradual incline, but 

 I believe that this is a deceptive appearance due to the line of section 

 running at a very low angle to the scarp, and cutting it very 

 obliquely, since a close examination of the drifts shows that they are 

 banked against a very steep slope. 



On the west side, the old valley-floor, standing two or three feet 

 about high-water mark, extends from the cliff of chalk for 60 or 70 

 yards in a very gently sloping terrace which is strongly suggestive 

 of a tidal flat, but toward the eastern boundary of the hollow the 

 chalk floor sinks below beach-level. 



This old hollow has been entirely filled in by drift deposits in 

 Glacial times, but since that time a puny stream of surface water, 

 which drains to the beach, has cut a narrow V-shaped ravine through 

 the midst of the drifts. The sea has also eaten back further into the 

 coast-line than where the chalk stands higher, and has thus formed 

 the little recess of the South Sea Landing in whose nearly vertical 

 cliffs, from 100 to 125 feet in height, most excellent sections of this 

 curious infilling material are revealed. 3 



1 Read at the Brit. Assoc. Newcastle, before Section C (Geology), Sept. 1889. 



2 For description of the Bridlington and Dimlington beds see Clement Reid's 

 Survey Memoir on Holderness, pp. 8-26, and my papers in Geol. Mag. Dec. II. 

 Yol. VIII. pp. 535-546, 1881 ; and Q.J.G.S. vol. xl. p. 312, 1884. 



3 These sections have already attracted some attention from geologists, and are 

 mentioned by J. Phillips, Geol. of Yorksh. pt. i. 3rd ed. p. 91 ; T. Mellard Reade, 

 A Traverse of the Yorkshire Drift, Proc. Liverpool Geol. Soc. 1882-3, p. 11 ; Wood 

 and Rome, Q.J.G.S. vol. xxiv. p. 180 ; and J. R. Dakyns, Proc. Yorks. Geol. and 

 Polyt. Soc. vol. vii. p. 249 (1880). 



