A HISTORY OF NORFOLK 



together with the seed that has been sown, the material being heaped 

 against a neighbouring bank. 



The sands (sometimes termed ' Middle Glacial ') which underlie 

 the main mass of Chalky Boulder Clay have been exposed on the coast 

 south of Winterton. Here and further south in Suffolk they show 

 comparatively little disturbance. They are false-bedded, they contain 

 much coal-smut or comminuted fragments of lignite, and sometimes 

 grains of chalk. At Caister, near Yarmouth, and again at Billockby 

 and other places, many species of shells have been recorded by S. V. 

 Wood, jun., and Mr. F. W. Harmer, who regarded them as belonging 

 to the deposit, and to a comparatively mild Interglacial period. It is, 

 however, much more probable that the bulk of the shells, which are 

 worn and fragmentary, were derived from the Crag.* 



Pebble-beds are met with occasionally in the sands, as near Ched- 

 grave, north of Loddon, Heckingham and Haddiscoe. 



Sometimes the sand is indurated. This happened at Mackie's 

 Nursery, near Norwich, from the infiltration of water charged with 

 carbonate of lime from the overlying Boulder Clay. The sand was 

 cemented with the calcareous matter, and was in old times locally used 

 as a building-stone. 



Occasionally we find coarse gravel under the Boulder Clay, as at 

 Ashwell Thorpe, and also at Roydon, near Diss, where many derived 

 Jurassic and other fossils have been found. This gravel may be regarded 

 as a torrential deposit, formed by the melting during its earlier stages 

 of the ice-sheet which formed the Chalky Boulder Clay. 



The gravels and sands yield water locally, upheld by the Lower 

 Boulder Clay or by the loams of the Contorted Drift. At Holt copious 

 springs are thrown out beneath the gravels and sands which form the 

 plateau above the marly Contorted Drift. At Costessey, St. Walstan's 

 Well was in old times a famous healing spring, and this issues from the 

 Glacial sands. 



Many of the springs along the Cromer coast are ferruginous, their 

 courses being marked by dark red stains on the cliff faces. 



A good deal of ochreous matter locally occurs in all the gravels of 

 Norfolk, and the Rev. A. R. Abbott found slag in the hollows known as 

 Weybourne Pits, which he attributed to early British workings for 

 iron ore. Iron slag also occurs on Beeston Pleath, but Mr. C. Reid 

 considered that the ore might possibly have been brought. 



Bog iron ore occurs in some of the valley gravels ; and it may be 

 mentioned that iron-pan, a term applied to cemented layers of sand and 

 gravel, is met with at various horizons and localities. 



Here and there beneath the Chalky Boulder Clay there are beds of 

 finely laminated loam similar in character to those before noticed in the 

 midst of the Lower Boulder Clay. Some of these masses are remarkably 

 contorted, as may be seen near Diss railway-station. At Hedenham 

 there was formerly a Roman kiln where the loam was worked. 



* See H. B. Woodward, ' Glacial Drifts of Norfolk,' Proc. Geol. Assoc, vol. ix. p. 113. 



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