5IO PLEISTOCENE. 



•this is due their agi-icultural eminence. In tlie good old times it has been 

 very extensively used as a manure, hence the number of old marl- or clay-pits 

 scattered about the county, in the area occupied by Upper and Lower Boulder Clays. 

 Some of the richest land in north-eastern Norfolk is situated on the Contorted Drift. 

 Wheat is extensively grown on the heavier lands, and Barley on the lighter soils. 

 Much of the best Barley, for wiiich Norfolk is celebrated, is raised on thin chalky 

 soils of the Lower Glacial Drift, in the neighbourhood of Stiffkey, Wells, and 

 Burnham. Near St. Albans and Luton the strawplait industry is due to crops 

 largely grown on the Glacial Drifts. 



In the neighbourhood of Hardwick, Tivetshall, Diss, etc., bricks known as 

 ' clay-lumps ' are made from the Chalky Boulder Clay. The material dug is 

 mixed with chopped straw, moulded, and then dried in the sun. Ordinary bricks 

 are made in some localities from the Boulder Clay. A boulder of bituminous 

 shale (probably from the Kimeridge Clay) was found at Anmer, in West Norfolk, 

 and used as fuel.^ 



Plateau or Cannon-shot Grazed. — Scattered over the high grounds of Holt and 

 Cromer, and resting on the Chalky Boulder Clay in many places in West Norfolk, 

 at Hempton near Fakenham, at Wymondham, Tasburgh, Poringland, Strumpshaw, 

 and Mousehold, near Norwich, there are great accumulations of coarse boulder 

 gravel — gravel containing large blocks of flint and even paramoudras, all more or 

 less foiled and knocked about. Some few igneous rocks occur also, as well as 

 pebbles of quartz and quartzite. To these deposits the name Cannon-shot gravel 

 was applied by Mr. Wood, because the majority of the stones in some places are 

 "rolled into the shape and dimensions of the now obsolete cannon-shot of from 

 I albs, to 32lbs. calibre." The gravel is from i to 45 feet thick. 



The deposit seems in many instances to be intimately connected with the Chalky 

 Boulder Clay, and it may perhaps have resulted in part from the melting away of 

 the ice-sheet that formed the Clay ; hence it has sometimes been termed Flood 

 Gravel. It is, indeed, an accumulation that bears evidence of having been formed 

 in a tumultuous way, but the Chalky Clay itself does not yield such large flint 

 boulders in abundance. The question is, whence came the flints — for the deposit 

 is not often found directly on the Chalk, otherwise we might account for it by 

 ordinary marine action on a foreshore of that formation. It is possible that during 

 later Eocene and Miocene times accumulations of flints were formed by subaerial 

 action on the Chalk surfaces of West Norfolk, and that in Glacial times they 

 furnished material for the gravels.- The accumulations of coarse gravel are, how- 

 ever, not of one age, as similar beds occur occasionally in the older Glacial Drifts. 

 In some instances, too, these coarse gravels assume the form of Eskers, as near 

 Blakeney, in Norfolk.^ Mr. Whitaker has also noticed Eskers near Great 

 Massingham. Near Wells, and also at Roydon, near Diss, the gravels contain 

 large rounded blocks of Chalk as well as flint. The gravel at Wells has yielded 

 remains of the Mammoth, while that near Diss contains many derived fossils. 



The gravels are largely dug for mending roads, and the large flint boulders have 

 been used for building, and even for paving some of the streets of Norwich, where, 

 under the name of "cobbles," " Norfolk dumplings," or " petrified kidneys," they 

 form stumbling blocks both for man and beast. S. Woodward, in his "Observations 

 on the Round Towers of Norfolk,"* noticed that, with one exception (West 

 Dereham), all these churches were built of flint boulders, and he stated his 

 conviction that they owed their circular form, not to any peculiar style, but had 

 been thus built from necessity, in consequence of the absence of freestone from 

 the soil. 



Trail. — In describing the chai-acter of the latest superficial deposits, the Rev. 

 Osmond Fisher has treated of the ' warp of the drift,' so called by Mr. Trimmer. 

 This warp or general surface soil is influenced in its character by the stratum on 

 which it rests, but at the same time often contains ingredients which cannot have 



' J. Gunn, P. Geol. Assoc, iv. 44. 

 2 Trans. Norfolk Nat. Soc. iii. 444, 447. 



■'' Proc. Norwich Geol. Soc. i. 263, and G. Mag. 1883, p. 43S. See also Geol. 

 Fakenham, etc. (Geol. Survey), p. 35. 

 * Archaeologia, xxxiii. 7. 



