Vol. 69.] AGE OF THE SUFFOLK VALLEYS. 607 



(d) Deben Valley. — The borings in this valley near Wood- 

 bridge are more difficult of explanation. Of about fourteen 

 well- sections recorded, ten are conformable with regard to the 

 position of the top of the Chalk and Eocene beds, but one is 

 anomalous. The explanation of this singular section was discussed 

 by Mr. Whitaker and others, 1 opinions being divided ; suggested 

 causes were a Glacial channel, a huge Chalk solution-pipe, land- 

 slipping, and trough-faulting. None were satisfactory, but the last 

 seemed to be the best. The following is the boring as recorded, 2 

 the square brackets indicating the proposed grouping of the 

 strata : — 



Soil 



'Trial boring for Woodbridgc Waterworks Co., 1901. 

 (Height above sea-level = IS feet.) 



Thickness in 

 feet inches. 

 2 



/'Sand 4 



I Gravel and flints 3 



Loimy sand (sandy loam) 4 



I Sand 2 



■{ Gravel 3 



[Drift ?] 



Sand and shingle (loamy gravel). 

 Mottled sand (somewhat loamy). 

 Sand and shingle (fine gravelly 



sand) 8 



(Grvey sand (dark-brown silty sand) 1 



Fine sand (shelly sand) 7 



I Fine sand, shingle, and Crag 



■{ (gravelly sand) 60 



I Black mud (fine gravelly loam)... 1 

 i Crag with shells (shelly sand, 



{ Turritella) 25 



[London Clay ? f Claystone (septaria) 



[Crag ? 

 95§ feet.] 



nearly 

 20 feet] 



[Beading 



' Beds ? 



nearly 



41 feet.] 



Chalk (and i 



] Blue clay (stiff grey clay) 15 



[ Sand and pebbles 3 



/"Dark sand (grey firm sand, slightly 



j loamy) 6 



J Yellow sand and clay (brown 



j sand) , 15 



I Blue clay (grey) 2 



[ Fine yellow sand (brown) 16 



hits) 55 



Depth in 



feet inches. 



2 



132 

 133 

 148 

 152 



159 



174 

 177 

 193 

 249 



37 5 



38 5 

 45 5 



106 



107 6 



The Chalk was thus reached at — 1 75 feet O.D., while its surface 

 in wells close by occurs at from — 20 to —47 feet O.D. There is 

 no evidence of faulting or similar disturbance of the beds anywhere 

 in the surrounding area (faults are very rare in Suffolk, and when 

 they occur are of trivial character), and in view of glacial distur- 

 bances on a large scale seen in Suffolk valleys, it seems more satis- 

 factory to regard the case as one of a buried glacial channel similar 

 to those in the neighbouring valleys. It is noteworthy that a 



1 Whitaker, 1903 (20) p. 36. 



a ' Water-Supply of Suffolk ' Mem. Geol. Surv. 1906, p. 128. 



