Vol. 54.] LENHAM BEDS AND COKALLINE CRAG. 333 



being sufficiently shown by numerous sections ; but the difficulty of 

 boring through loose and wet sand is very great, and requires much 

 patience, especially when a depth of 15 or 20 feet is reached.^ 



The different borings made in the neighbourhood of Orford show 

 that the junction between the London Clay and the Coralline Crag 

 has an average dip, in a northerly or north-easterly direction between 

 Butley Creek at Gedgrave and Sudbourne Hall, of 8 feet to the 

 mile ; beyond the latter place it lies too deep to be reached by my 

 apparatus.^ The gradient between Sutton and Gedgrave is about 

 6 feet per mile (see fig. 5, p. 328), and between Sutton and 

 Tattingstone rather less. At the last-named locality the Crag-beds 

 approach the 100-foot contour-line, but occur somewhat below it. 

 At Sutton, as we have seen, they rest upon the London Clay at 

 20 feet above high- water mark, and they are there about 40 feet 

 thick in vertical section. 



Tracing the Coralline Crag from Sutton towards the north-east, 

 it is found at Boyton occurring slightly below the level of the 

 marsh, but at present it is not accessible there — unfortunately so, 

 as some species were obtained in abundance at Boyton which are 

 not common at Gedgrave and Sutton. Both the Coralline and Bed 

 Crags and the nodule-bed also are present there, and it may be 

 possible hereafter, by boring, to clear up the question of the true 

 position of the last-named deposit. So far as one can judge from the 

 available evidence, the nodule-bed formerly exposed at this locality 

 is below the Coralline Crag.^ The shells obtained by the coprolite- 

 diggers were so mixed that it was impossible to say certainly from 

 which formation they had been derived. Some geologists have 

 suggested, but I think without sufficient evidence, that at Boyton 

 there is a Bed Crag fauna of a special and distinct character. I visited 

 the locality in 1897 : no section was then visible, but on the site of 

 one of the old workings there was a heap of soil, and from it I picked 

 out a few specimens or fragments of the following (all of them being 

 later Bed Crag forms, and of the usual Bed Crag colour) : — 



Purpura lapillus. 

 Buccinum undatum. 

 Trophon antiquus. 



,, contrarius. 

 Turritella incrassata. 

 Pecten opercularis. 

 Cardium edule. 



„ grcenlandicitm. 



„ Parkinsoni, 

 Cardita senilis. 



Astarte Omalii. 

 Cyprina islandica, 

 Tellina ohliqua. 



,, crassa. 



„ prcetenuis. 

 Mactra solida. 



„ ovalis. 



„ elliptica. 

 Mya arenaria, 

 „ truncata. 



^ If some light and portable apparatus could be devised, suitable for boring 

 through wet and sandy soil, it would be of great value to amateur geologists. 



^ The greatest depth attained by me was 31 feet. 



^ See also Whitaker, Mem. Geol. Surv. 1886, Aldborough, p. 9. On one of 

 Mr. Wood's survey-maps is the following note : — ' This rectangular mark [shown 

 also in fig. 4, p. 326, of the present paper] is that which Mr. Robert Bell has 

 drawn in a copy-map sent to me, to represent the coprolite-trench from which 

 so many shells are obtained. He says there is about 18 inches of Coralline, 

 overlain by 30 inches of Red Crag and sand.' 



