2l8 YORKSHIRE NATURALISTS AT FLAMBOROUGH HEAD. 



attention to those beds of sand and gravel and laminated clay which rest upon the 

 upper purple clay, more particularly in the cliffs opposite Sewerby, and known as 

 the ' Sewerby Gravels.' Proceeding, the ancient chalk cliff which runs inland was 

 seen, evidence that previous to the great ice age the sea covered Holderness, the 

 line of coast being in the direction of Burton Agnes, Craike Hill, and Hessle. 

 Some pre-glacial beds of sand and chalk debris were noted. Then evidence of the 

 great pre-glacial valley was seen, filled up during the glacial period and since, at 

 Dane's Dyke, partially re-excavated by denudation. The fine cliffs of the upper 

 chalk were now passed, exhibiting in some places fine examples of contortion, the 

 result of lateral pressure. At South Landing the cliffs were ascended, and the 

 way taken across the fields to the lighthouses and to that beautiful bay known as 

 Selwick's Bay, although on the Ordnance map it is erroneously named Silex Bay. 

 Here were some special matters of interest ; in the centre of the bay a fault occurs, 

 the strata being much bent and broken, and from this cause the sea has been 

 enabled to make an inroad and form Selwick's Bay. The fissures of the broken 

 chalk have since been beautifully filled by calc spar. It might have been stated 

 that on nearing the extreme corner of Flamborough Head on the south side, flints, 

 both nodular and tabular, begin to appear, and on the south side of Selwick's Bay 

 they were seen in vast numbers. Mr. Lamplugh proved the existence of this fault 

 by showing that the chalk on the north side of the slip contains no flints whatever, 

 and they do not re-appear till a little distance to the north. A very curious matter 

 was pointed out here — a mass of blue Speeton clay, stranded on the top of the 

 chalk, which contains many of the characteristic Neocomian fossils. Here, too, 

 were a couple of isolated pinnacles of white chalk standing out like sentinels. 

 They have not yet been named, and it was humorously suggested that in honour of 

 the leaders of the party, they should henceforward be known as the ' Cole and 

 Lamplugh , Rocks. ' Keeping the edge of the cliff, splendid opportunities were 

 afforded of observing the beautiful effects of the erosion of the chalk cliffs by the 

 waves. Here were arches, caves, and miniature bays in abundance ; pillars and 

 pinnacles in other places, as in the case of the King and Queen Rocks. The latter 

 were formerly the supports of gigantic sea caves, but since the falling in of the roof 

 they stand out in melancholy isolation, destined in their turn, before the ceaseless 

 attacks of the waves, to finally disappear. At Breil Point was noticed a ' blow- 

 hole,' where the water is violently ejected from the force of the compressed air, and 

 flies in fine spray at right angles to the rock. These ' blow-holes ' will eventually 

 become caves — thus the work of denudation actively goes on. The cliffs are here 

 capped with boulder clay, which weathers most curiously, as in Filey Bay, into 

 knife-shaped edges. The party now arrived at Thornwick Bay, where, after a 

 short stay, the way was taken along the cliffs once more — arriving at length at the 

 wonderful earthwork known as Dane's Dyke. This great defensive work runs 

 north and south, a distance of two and a half miles from cliff to cliff, and is of 

 nearly uniform height all along, being about 18 feet above the level of the ground, 

 and having a ditch 60 feet wide on the outside. Although the name ' Dane's 

 Dyke ' is used when speaking of this earthwork, it is evidently a misnomer, as 

 excavations carried on systematically by competent archaeologists, have discovered 

 weapons and other relics of a higher antiquity than the Danish invasions of 

 England. When standing upon the summit of this mighty rampart, one could not 

 but muse and conjecture who were its builders, and who were the fierce invaders 

 who rushed up its slopes engaged in deadly combat with its defenders. The page 

 of history is silent as to those tremendous Yorkshire battles ; tradition is very 

 obscure ; but it must be admitted that the people who constructed this rampart 

 must have been well advanced in their ideas of military defence, and they must 

 have had also great method and discipline in constructing it. This was, most 

 certainly, a very impressive sight. Farther on, near Scale Nab, were seen some 

 extraordinary contortions in the chalk cliffs, the strata being bent and folded most 

 remarkably. The explanation for this must be the same as accounts for the con- 

 torted limestone at Draughton, that is, immense lateral pressure long after the 

 strata were deposited, and when they were covered by an immense thickness of 

 over-lying rocks. The train was now taken at Bempton for Bridlington. Other 

 members of the section had worked independently. Mr. S. Chadwick (Malton), 

 junior secretary of the section, had worked assiduously for fossils near the south 



Naturalist, 



