yy PKOF. J. PRESTWICH ON THE RELATION OF THE 



The proportions, as might be supposed, vary in every pit, and 

 even in different parts of the same pit : but the constant presence of 

 the first four constituent parts, and the absence of certain others, is 

 a remarkable feature, and enables us to recognize these beds when 

 other evidence is wanting, and to distinguish them from beds of 

 Lower Tertiary, Uagshot, or Glacial age with which they might 

 otherwise be confounded. 



Near Halesworth, 6 miles JSF.jST.W. from Westleton, where sub- 

 angular flints are more abundant, the shingle consists of : — 



1. Flint-pebbles 50 



2. While quartz-pebbles 10 



3. Subangular flints 34 



4. Chert&c 6 



100 



At Henham, on the other hand, the proportion of flint-pebbles to 

 the other constituents is larger. In a pit in the Park, where there 

 were about 20 feet of shingle, the upper 6 feet consisted of horizontal 

 layers, while the lower beds exhibited an oblique lamination as good 

 as that figured by Mr. 8. V. Wood in the Red Crag at Bawdsey 

 Cliff as typical of current-bedding*. 



At Blythburgh and Eeydon, the Westleton Beds are seen in the 

 same relation to the Glacial Beds, and it was in a pit near the 

 latter place (Quart. Journ. Geol. Soc. vol. xxvii. p. 462), that I 

 found in a seam of pebbly sand concreted by iron-peroxide numerous 

 casts and impressions of Mytilus edulis, double, and in all stages of 

 growth. The beds generally have, however, been extensively decal- 

 cified, so that shells are extremely scarce. 



At Easton Bavant cliff, the superposition of the Westleton Shingle 

 on the Chillesford Clay and Sands, both of which latter are here 

 fossiliferous, is very distinct, while the former exhibits very clearly 

 the special characters which serve to distinguish it from Glacial 

 beds. 



It is composed as under : — 



Per cent. 



1. Flint-pebbles 52 



2. White quartz-pebbles 18 



3. Subangular flints 20 



4. Worn fragments of chert, quartzite pebbles, one large pebble of 



indurated clay with indistinct vegetable impressions 10 



100 



Here also I found, as at Eeydon, a thin seam of ironstone inter- 

 calated in the upper part of the Pebble-bed with casts and im- 

 pressions of Cardium (0. edule?), Mytilus (M. edulis'^.), Littorina, 

 and Katica. 



Since I visited this district it has been described by Mr. Whitaker, 

 and allowing for changes in the coast-sections caused by the en- 

 croachment of the sea, our observations are in close agreement. He 



* ^nn. & Mag. Nat. Hist, for March 1864, p. 3. 



