WESTLEION BEDS TO THOSE OF NORFOLK, ETC. 97 



the old designations of "Plastic Clay "and " Mottled Clays," which 

 would specialize characters common in formations of Tertiary as well 

 as of Secondary age. 



The localities where the Shingle Beds are most extensively de- 

 veloped, and where the joint lithological and palseontological cha- 

 racters are best combined, will be found in the Ordnance Map, Sheet 

 49 W. and 50 E. From this centre I will first take their range 

 northward. 



Between Westleton and Dunwich there is a large tract of common, 

 formed by low hills of pebbly shingle, which extends with little 

 interruption to Blythburg and Southwold, and thence to Easton 

 Bavant and Covehithe, forming a belt some 2-4 miles wide and 

 1 miles long. The higher ground is everywhere capped by Boulder- 

 clay, from beneath which the Shingle Beds crop out, whilst on the 

 coast the Chillesford Clay rises from beneath the latter (except where 

 it has been denuded before the deposition of the Shingle), thus 

 defining accurately the stratigraphical position of the Shingle Beds. 



The Shingle consists of flint pebbles as well rounded and forming 

 beds as massive as the Tertiary Beds of Blackheath or Addington, 

 with subordinate sands and thin clays. Erom two of the closely 

 adjacent large pits on the common, the accompanying general 

 section (fig. 1) is constructed from notes taken some years since. 



Unlike the overlying Glacial Beds with their northern drift, we 

 have evidence in this Shingle of a decided transport from the south- 

 ward in the presence of subangular worn fragments of Chert and 

 Eagstone of the Lower Greensand, probably of Kent, a fact to 

 which I formerly drew attention *. With these are associated a 

 considerable proportion of small white quartz-pebbles and a few 

 large flattish ovoid pebbles t of light-coloured Quartzite and Sand- 

 stone, with small pebbles of Lydian stone and jasper &c. There 

 is a total absence of the larger darker red and grey rounded 

 quartzite-pebbles (cobbles) of the New Bed Sandstone, so common 

 in the Glacial Series. The average composition J of this Westleton 

 Shingle at Westleton may be roughly taken as under : — 



Per cent, 



1. Black flint-pebbles 60 



2. Wliite quartz-pebbles, with a few rose-coloured 20 



3. Subangular flints, not stained 10 



4. Subangular fragments of grey pin-hole ragstone and dark yellow 



chert ' 4 



5. Large flattisb pebbles of light-coloured quartzite, light and dark 



sandstones, and small pebbles of veinstone, Lydian stone, and 

 jasper, with a few subangular fragments of black chert (Carbo- 

 niferous ?), of a dark slaty rock, and of quartz 6 



100 



* Op. cit. pp. 461 and 477 (1871) ; and British Association Eeports for 1881, 

 p. 620. 



t They are very similar in shape and colour to the recent quartzite-pebbles 

 on the Chesil Bank. 



+ The determinations in all cases can only be given approximately. For 

 reasons given in Part 11. of this paper these proportions may not be quite 

 correct locally ; but as the same error, if any, runs through all the localities, 

 the general result is not seriously aflected. 



Q. J.G.S. No. 181. H 



