106 S. V. WOOD, JUN., AND F. W. HARMER ON THE 



Trimley outliers, the only difference being that the Kirton protru- 

 sion is partially capped with a patch of the Upper Glacial. 



Looking at the lines of section, as far as they are warranted by 

 the actual exposures, it would appear as though the interglacial 

 valleys thus excavated were, though much wider, shallower than 

 the present ones ; but there are facts which point to the inference 

 that in the same way that the valley of the Yare was deeper inter- 

 glacially than it now is, so that of the Deben (and therefore, as an 

 almost necessary sequence, the other valleys of South Suffolk) was 

 somewhat deeper interglacially also. For instance, the Middle 

 Glacial overlain by the Upper seems to plunge down so completely 

 into the bottom of one of the principal lateral valleys which open 

 out into that of the Deben, that, unless this were the case, the 

 valley could have had no outlet. Section XXI. illustrates this, as 

 well as the position of the important outlier of the Contorted Drift 

 at Woodbridge and Hasketon, the much steeper character of the 

 interglacial valley-slopes formed by it being proved by the great 

 excavation in the Middle Glacial on the east, and by the well sunk 

 through the Upper and Middle Glacial on the west side of it. In 

 this section the sand overlain by the Upper Glacial Clay which fills 

 the bottom of the rivulet- valley, is referred to the Middle Glacial 

 (which is clearly recognizable where it underlies the Upper Glacial 

 above the railway-cutting) ; but there is some uncertainty whether 

 it be not the sand formed by the dissolution of the Crag ; but as it 

 descends below the general level of the London-Clay floor of the 

 Crag (which is well exposed in an adjoining valley where the Middle 

 Glacial sweeps down below it in the way shown in this section), we 

 have shown it as belonging to that formation. 



It is not improbable also that the bed 10, represented as valley- 

 gravel, through which the Finn river and the Deben are represented 

 as cutting, may be underlain by Middle Glacial gravel, or be that 

 gravel postglacially reconstructed. 



The sinking of the well, shown in fig, 22, was watched and 

 measured daily by one of us, and was interesting as furnishing a 

 perfectly clear scarped section of this tableland down to the Crag- 

 level, at a point but little more than half a mile from the numerous 

 excavations in the Contorted Drift overlain by Upper Glacial, which 

 occur at the Woodbridge and Hasketon brick-pits ; and it proved 

 that this Drift, and any other formation, such as the Chillesford 

 Clay, which may have existed between it and the Red Crag, had 

 been completely removed before the deposition of the Middle Glacial. 

 It also disclosed that the band of broken shells a few feet below the 

 junction of the Middle with the Upper Glacial, which is so constant 

 around Yarmouth, and from which were obtained the species given 

 as from this formation in the Supplement to the ' Crag Mollusca/ was 

 also present here ; and we obtained from it fragments of the fol- 

 lowing species : — Tellina crassa, Gmel., Mya arenaria, Linn., Mactra 

 arcuata?, Linn., Cyprina islandica, Sow., Cardium edide, Lin., Pec- 

 tunculus glycymeris, Linn., Pecten opercularis, Linn. The particulars 

 of the sinking were as follows : — 



