INTRODUCTION. XXVil 
Post-glacial, but with respect to that which caps Mousehold Heath (see Section O), 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, 7. ¢. 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 mto the cannon-shot form. The 
absence of these thick gravels over all the southern part of Hast 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 Chiff, March, Hunstanton, and the 
Nar Brickearth. 
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 fluminalis, with the marme 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 
