374 Rev. W. B. Clarke on the Geological Structure 



better than 6 feet per mile. A remarkably near agreement with this is 

 afforded by the slope from Sudbury to Harwich, which makes the fall of the 

 chalk about 6 feet per mile ; at Sudbury the Stour is about 70 feet above the 

 salt-water lowest level, and the cliff there is about 30 feet above the Stour ; 

 and consequently the difference of chalk level is about 150 feet in 25 miles. 



No. 17. — Layham brick-kiln, 1 mile south of Hadleigh, 1^ mile north of 

 No. 16, and about 30 feet above that level. 



Feet. 



1 . Diluvial gravel 



2. London clay, indigo blue, with pyritous nodules, black pyritous wood, yellow 



streaks of sulphur, containing septaria, shells (too crumbly to be ascertained), 

 and sharks' teeth : the clay becomes brown 60 



3. Plastic clay — sand 3 



4. blue clay 4 — 7 



sand (depth not known) 



Total.. 67 



In bed 2 there is a slip of at least 20 feet. 



No. 18.— Wells at Hadleigh, sunk Nov. 1827. 

 A. B. 



Feet. Feet. 



1. Diluvial gravel 12 — 



2. Plastic clay — pure blue clay 90 70 



3. Chalk 28 30 



Total.. 130 100 



The well A. is on a level with the river, and shows that the chalk at Had- 

 leigh has been scooped into a hollow, since, at Shelley, it lies level with the 

 river ; and here, allowing 7 feet for the descent of the stream at the mill-lock, 

 and 23 feet for the difference of height of the chalk in the river's bank at 

 Semer and Shelley, it will make the slope of the chalk 4 feet per mile, and 

 the hollow at Hadleigh 95 feet deep, the chord being 2^ miles. 



For the wells between Hadleigh and Ipswich, see No. 78. 



Nos. 19 to 23. — 



Wells at Kersey (19). Whatfield (20). Semer (21). Monk's Eleigh (22). Bildestone (23). 

 2m.N.W. 2im. N. 3 m. N.N.W. 4§m.N.W. 4§in.N.N.W. 

 Hadleigh. Hadleigh. Hadleigh. Hadleigh. Hadleigh. 

 Diluvial clay 75 ' 40 — 62 60 



Gravel — — 50 



Chalk — G6 22 



Total.. 7.5 106 72 62 60 



' Sandy. - The chalk rises 7 feet above the river, about 3 feet below the level of this sur- 

 face, only one mile distant. 



