108 S. V. WOOD, JTTN., AND F. W. HARMER ON THE 



between them, and occupying valleys interglacially denuded in the 

 former in the manner already described ; for, with the exception of 

 these few exposures, the sides of the Gipping valley are occupied by 

 the Middle Glacial, like those of the Waveney. 



The valley of the Little Ouse and parts of the valleys of some of 

 its tributaries are the only instances in Norfolk and Suffolk which, 

 so far as we are aware, afford any indication of Preglacial origin. In 

 this valley, about Thetford (as also in that of the Thet, a tributary 

 of the Little Ouse), the Middle Glacial is not present, though it sets 

 in higher up it to the eastward. A chalky deposit, very gritty, form- 

 ing extremely light land, and much resembling in aspect the Con- 

 torted Drift as it exists round Holkham, in North-west Norfolk, 

 occurs within the slopes of the Thet and Little-Ouse valleys, as well 

 as on the heights at and around Thetford ; but whether this is the 

 Contorted Drift, or an abnormal form of the Upper Glacial, we have 

 not been able to satisfy ourselves. There is also at the brick-kiln 

 on the high ground about a mile north of Thetford a laminated 

 brick-earth overlying a bed of marl or reconstructed chalk which 

 rests on glaciated chalk, and which we have regarded as part of the 

 Contorted Drift. It is possible, however, notwithstanding their not 

 being confined to the valley, that this and the gritty deposit just 

 referred to may represent the interglacial bed (a) of the Yare valley 

 which we have already described and shown in sections Y. & VI. 

 Further east, up the Little-Ouse valley, and near to the common 

 source of that river with the Waveney, there occur some exposures 

 of brick-earth that seem also to belong to the Contorted Drift. Of 

 these one is 6 furlongs north by east of Garboldisham church, another 

 about the same distance west of Knattishall church, and the third 

 at Fen Street, Redgrave, the last of these being within the Waveney 

 valley, whose source is a mile west of it. For this short distance, 

 therefore, the Waveney valley is of Preglacial origin, like that of 

 the Little Ouse. These three exposures of brick-earth are all within 

 a valley which seems to have traversed a hill of chalk stretching 

 north and south from the neighbourhood of Ixworth to that of 

 East Harling, and which is now mostly covered by the Upper Gla- 

 cial. Assuming this brick-earth to be the Contorted Drift, then 

 that deposit, instead of covering a generally level floor, as it does 

 to the eastward, here enters and lies in a valley of Preglacial origin, 

 of which the Little-Ouse valley in this part is a re-excavation. 

 Whether this valley was an estuary at the time of the deposition of 

 the Contorted Drift, or merely a submarine channel, there is not 

 evidence to show ; but in view of the very considerable submergence 

 of Norfolk during the Lower Glacial period, which the dimensions of 

 the marl masses that are imbedded in the Contorted Drift appear 

 to indicate, an estuarine condition of the Little-Ouse valley during 

 the deposition of that drift is difficult to understand. 



Two other small river-valleys occur in South Suffolk — that of the 

 Brett, which flows by Hadleigh into the Stour, and that of the Box- 

 ford, another tributary of the Stour. The country between these 

 is occupied by a tableland of Upper Glacial clay, while along the 



