UEV. K. HILL n.V WKLLS IX WEST SUFFOLK HOULDKU-CLAY. 587 



seen, but not wlmt it rested on, except that at one spDt the work- 

 men had struck an exc('ssi\ely hard {j^ritty bed, ai)[(:irently cemented 

 by carbonate of lime. Botli upper and lower clay were well .shown 

 by freshly cut faces, and both were b}' no means homogeneous 

 masses. 



The appearances both at Bury St. Edmund's and at Sudbury are 

 quite different from what I should ox])ect in a mass resulting from 

 the abrasion by a glacier of its bed. As no one (so far as 1 know) 

 has ever seen a so-called " ground-moraine '' beneath an existing 

 ghicicr, we can only argue by analogy. According to the sui)posed 

 method of formation I should expect this to possess a structure 

 analogous to that produced when a sledge is dragged over soil. 

 No section shows such appearances. 



I think it worth while to call attention to these facts, as a 

 satisfiictory theory of the origin of this vast mass must give a satis- 

 factory account of its phenomena. I have no theory of my own 

 iit present to propound, but I hope to continue observations on this 

 interesting and difficult subject. 



Note on the Cockfield Post-Office Well. 



Localitif. — Cockfield Post Office, rather more than half a mile 

 N.W. of Cockfield Kailway Station. Height above O.D. about 

 270 feet. The bed of the brook is about a quarter of a mile east, 

 less than 40 feet below. 



feet. 



(1) Yellow clay (Brick earth?) about 8 



(2) Red gravel with large flints 7 



(3) Yellow clay with much small chalk 3 



(4) Blue Boulder-clay with much chalk in well-rounded pebbles... 40 



(5) Broken lurops of chalk and flints 5 



(6) Blue clay with sub-rounded chalk fragments, base not reached. 



The well was continued in (6) to a total depth of 83 feet, and 

 then abandoned, no water having been met with below the gravel. 



In (4) were masses of dark calcareous clay, full of ammonites, 

 &c. (Kimmeridge Clay?), often scratched. At the depth of 22 feet 

 a chalk boulder at least two feet long was met with. When (5) was 

 reached it was at first supposed to be the surface of the Chalk itself. 

 In (6) the chalk fragments were mostly as large as pigeons' eggs ; 

 flints were certainly less numerous than in (4), both according to 

 my own observation and the opinion of the well-sinker. The well 

 was begun in March 1800, and abandoned in May of the same year. 



Discussion. 



Prof. PRESTWicn remarked that intercalated beds of gravel and 

 sand were common at different levels in the more northern Boulder- 

 clay, and that in parts of the Eastern Counties a bed of gravel, 

 from 1 to 20 feet thick, generally occurred in the centre of the 

 Boulder-clay. These formed small water-bearing beds, but the 



