GLACIAL BEDS. 505 



from the Sands at Hopton Cliff, near Yarmouth, present "a general Arctic 

 character." ' 



Mr. T. F. Jamieson has described beds of Drift sand and gravel on the eastern 

 border of Aberdeenshire, which contain fragments of shells, comprising forms 

 found in the Coralline, Red, and Norwich Crags, as well as in more recent 

 deposits, although all of the species, excepting Tdltna Balthka, occur in the Red 

 Crag.* The Bridlington shell-bed also contains fossils derived from the Crag. 

 Hence all difficulty is removed in seeking a northern derivation for the shell 

 accumulations in the so-called "Middle Glacial" Sands of East Anglia. More- 

 over, local geographical distribution of the MoUusca in the Crag period may 

 account for the peculiarities in the fauna. At any rate we are justified in making 

 the suggestion that the Middle Glacial shells may have been largely derived from 

 old Crag accumulations, now entirely destroyed or buried up beneath the waters of 

 the North Sea.^ 



The Westleton beds, which Prof. Prestwich described in 1870, from the village 

 of Westleton, between Yoxford and Dunwich in Suffolk, attain at this typical 

 locality "a thickness of from 30 to 40 feet, and consist of a series of stratified beds 

 of well-rounded flint-pebbles imbedded in white sand, and with two or three sub- 

 ordinate beds of light-coloured clay," looking as Prof. Prestwich remarked, 

 " more like the pebble-beds of Blackheath than any other beds in the Eastern 

 counties." ■* Continuations of these Westleton Beds have been traced to South- 

 wold, Dunwich (top of cliff), Henham Park, Halesworth, Haddiscoe, Thorpe- 

 next-Haddiscoe, and Chedgrave, near Loddon— localities which are rarely fossi- 

 liferous, and yield no distinctive species. In Norfolk, however, the Westleton 

 Beds have been correlated with the Bure Valley Beds, and with the Mundesley 

 Beds ; but the pebble-beds at Dunwich, which are clearly the same as those at 

 Westleton, occur in the ' Middle Glacial ' Beds of Mr. S. V. Wood, jun. Hence, 

 the Westleton Beds are in reality distinct from the Bure Valley Beds (Norwich 

 Crag Series), and they cannot be definitely correlated with the Mundesley Beds 

 which underlie the Lower Glacial Drift on the Norfolk coast.* (See p. 469.) 



The Middle Glacial Sands are frequently cemented into a hard rock, more 

 especially at or near the junction with the Chalky Boulder Clay above : this 

 induration is caused by infiltration of water holding carbonate of lime. An 

 example of this rock is seen in a pit, formerly known as Mackie's Nursery, near 

 Norwich. In West Norfolk and Suffolk the sands form extensive areas of 

 'waste land,' and there the light soil is liable to be drifted by the wind. (See 

 remarks on Blown Sand.) 



In some places in Essex the Middle Glacial gravel is very pebbly in nature, 

 which in Mr. Wood's opinion was probably due to the proximity of Tertiary 

 pebble-beds. In the neighbourhood of Hertford the Tertiary beds are capped by 

 pebbly gravel composed chiefly of flint and quartz pebbles. This is very distinct 

 from the more mixed gravel on the Chalk, and has been termed by Prof. Hughes 

 the ' gravel of the higher plain ' (or Hatfield Beds), to distinguish it from that in 

 the lower grounds.^ He suggested that it might be Pre-Glacial. It occurs also at 

 Barnet, Totteridge, etc., where it has been mapped by the Geological Survey 

 under the name of 'Pebble Gravel ' ;' but it is not always possible to separate it 

 from the Middle Glacial gravel. Some of this pebbly gravel has been described 

 by Professor Prestwich as equivalent to the Mundesley and Westleton Beds.^ 

 (Seep. 456.) 



1 Monograph Post-Tertiary Entomostraca, by G. S. Brady, Rev. H. W. 

 Crosskey, and D. Robertson, 1874, p. 103. 

 - Q. J. xxxviii. 145. 

 ^ P. Geol. Assoc, ix. III. 



* Q. J. xxvii. 461 ; see also Brit. Assoc, for 1881, G. Mag. 1881, p. 466, 1S82, 

 p. 29 ; and Wood and Harmer, Supp. to Crag Mollusca, p. xv. 



* G. Mag. 1882, p. 452. 



^ Q. J. xxiv. 283 ; Journ. Anthrop. Inst. vii. 162 ; S. V. Wood, jun. Q. J. 

 xxiv. 464 ; see also Dr. J. Mitchell, Proc. G. S. iii. 4. 

 ' Whitaker, Memoir .Sheet 7 (Geol. Surv.), p. 69. 

 ^ G. Mag. 1881, p. 466. 



