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QUARTZITE PEBBLES ON THE YORKSHIRE WOLDS. 



J. W. STATHER, F.G.S., 

 Hull. 



At a recent meeting of the Hull Geological Society (igth March 

 1903) a short paper with the above title was read by the present 

 writer. In this paper it was pointed out that on large tracts of 

 the Chalk Wolds of East Yorkshire, hitherto believed to be 

 devoid of erratic materials, large numbers of quartzite pebbles 

 occur, the geological history of which it is not easy to trace. 

 As the facts have a wide bearing on the geological history of the 

 district, it was thought a short preliminary account of them 

 might not be uninteresting to the readers of 'The Naturalist.' 



xAs is well known, the Yorkshire Wolds, composed in part of 

 flinty, and in part of flintless Chalk, extend in the form of a 

 rough crescent from Flamborough Head to the Humber. The 

 general dip of the Chalk is to the south-east, swinging more 

 to the east before it reaches the coast, and the general slope 

 of the upland is in the same direction, so that the higher parts of 

 the Chalk country are along the escarpments which overlook the 

 Vale of York to the west and the Vale of Pickering to the north. 

 To the south-east the Wolds sink gradually beneath the Glacial 

 Drift which covers Holderness, and the surface of the Chalk in 

 this quarter is considerably below sea-level. 



It must be noted, however, that the glacial deposits so abun- 

 dant in Holderness and the east coast generally, do not extend 

 to the higher parts of the Chalk Wolds, and that, though the 

 drift which covers their south-eastern flanks rises in some places 

 to a considerable height, there is a large area of high land to the 

 north and west entirely free from recognisable glacial deposits, 

 and this area has been mapped as driftless by the officers of the 

 Geological Survey. 



But on these high-level areas, in spite of the absence of 

 Glacial Drift, it has been found that quartzite pebbles occur in 

 large numbers. The pebbles vary greatly in size, but probably 

 their average diameter is from two to three inches. In colour 

 they vary from a dull yellow to a yellowish red. They are well 

 rounded, and in this respect resemble the Bunter pebbles so 

 abundant in the Midland counties. These pebbles are also 

 generally accompanied by pebbles of a hard, reddish sandstone, 

 somewhat larger than the quartzites, but fewer in number and 

 apparently not so waterworn. The scanty soil of the Wolds is 



1904 January i. 



