INTRODUCTION. xxvii 



Post-glacial, but with respect to that which caps Household Heath (see Section 0), and 

 that which caps the high land of Poringland and Strumpshaw (see Section L), 

 it seems the same as the gravel which has an extensive spread in West Norfolk (beyond 

 the limits of the map) ; since, like it, the gravel of these places, especially that of 

 Monsehold, contains beds of very large flints more or less rolled. These gravels of West 

 Norfolk set in almost along the same line as that about which the Middle Glacial sand 

 ceases, i. e. along a line extending from Hingham in the south, to Wells in the north. 

 This West Norfolk gravel is also composed almost entirely of large flints, which are 

 mostly so rolled as to resemble cannon shot. These cannon-shot gravels sometimes 

 contain masses of sand formed of chalk grains ; and as they are never overlain by the 

 chalky clay (9), but in a few instances have this clay, under them, it may be that, if not 

 of Post-glacial age, they are a local modification of such clay due to the action of some 

 powerful current over this part of Norfolk, which dissolved all the soluble part of the 

 morainic material forming that clay, and rolled the flints into the cannon-shot form. The 

 absence of these thick gravels over all the southern part of East Anglia is a peculiar 

 feature, but some thick beds of gravel, which occur on the Chalk Wold of Yorkshire 

 about Speeton and Bucton, seem to bear a relation to the purple clay (c) capping the 

 Wold at those places, similar to that which the plateau gravels of Norfolk bear to the 

 clay, No. 9. These Wold gravels, moreover, seem absent over the clay, c, where it occurs 

 further south, viz. over Holderness. 



The Post-glacial formations (No. 11). 



Several localities for shells from marine beds of this age are given in the ' Supple- 

 ment to the Crag Mollusca/ viz., Kelsea Hill, Paull Cliff, March, Hunstanton, and the 

 Nar Biickearth. 



The Kelsea Hill bed is in Yorkshire, adjoining the railway from Hull to Withernsea, 

 one mile east of the Burstwick station. It consists of sand and gravel, rich in individuals 

 of shells, all more or less rolled, and is specially notable for an abundant admixture of 

 the river shell, Cyrena jlnminalis, with the marine Mollusca ; pointing presumptively to 

 the inference that the bed was accumulated after the glacial submergence had given place 

 to emergence, so that a river flowed not far distant from this spot. The deposit was 

 described many years ago in Prof. Phillips' ' Geology of Yorkshire,' and more particularly 

 again by Mr. Prestwich in vol. xvii of the ' Quarterly Journal of the Geological Society/ 

 wherein a more copious list of Mollusca than our researches have afforded is given by Mr. 

 Gwyn Jeffreys. The whole of these consist of species still living, and with three or four 

 exceptions that are Scandinavian they are British. The geological position of this deposit 

 will be found fully examined in the paper from which the preceding section of the 

 Yorkshire Coast is taken ; and by the permission of the Council of the Geological Society 



