612 MK. P. G. H. B0SWELL OK THE [Dec. I913, 



the map of Suffolk (PI. LIV) shows that the Suffolk rivers are 

 largely dip-streams, although their direction changes from east- 

 north-easterly in the north of the count}' successively to easterly, 

 south-easterly, and southerly in the south of the county, in con- 

 sequence of the change in strike of the Chalk. It seems quite 

 likely that many of them are beheaded consequents belonging to a 

 larger drainage-system, which included originally the rivers now 

 reaching the Wash. 1 In the area (south-east of the watershed) 

 with which this paper deals, the form and direction of the rivers 

 and their tributaries would seem to suggest some amount of capture 

 here also, possibly behind an old Eocene escarpment ; bur the 

 country is now so plastered with Drift that it is almost impossible 

 to obtain evidence of any kind for or against capture. Many of 

 the subsequent tributaries are well developed ; but, if capture did 

 take place, the process does not appear to have gone very far. In 

 the case of the Stour, there is a possibility that the river from its 

 source to the Wixoe bend (see PI. LIV) may be the captured head- 

 waters of the south-eastward flowing consequent stream on which 

 Colchester stands — the Colne. The portion from Wixoe to Long 

 Melford would be subsequent, and the Sudbury portion another 

 consequent, and so on. The watershed between the Colne head- 

 waters and the Stour is only some 80 feet above the river-levels 

 (which are equal, the Stour at Wixoe being 170 feet O.D. and the 

 Colne at Great Feldham 164 feet O.D.), and consists of Upper 

 Boulder Clay and Glacial Sand, there being barely a mile of land 

 between the two valleys. The Drift round about, as shown by well- 

 borings, etc., is often more than 80 feet thick. 



The same kind of process may have gone on in the more eastern 

 part of the area, but may have been even less developed. The 

 general rectangularity, which is apparent independently on both 

 contoured maps and uncontoured geological maps, of the course of 

 the Brett Valley (Cockfield to Lavenham consequent, Lavenham 

 to Nedging subsequent, and Xedging to the Stour consequent 

 again), of the Deben Valley (Debenham to Bendlesham consequent, 

 Kendlesham to Woodbridge subsequent, and Woodbridge to the sea 

 consequent again), and possibly of the Aide Valley, is rather 

 significant. The map certainly suggests that the Butley Valley and 

 the upper portion of the Deben Valley were once united, but here, 

 as elsewhere, owing to the mantle of Drift, which is frequently 

 loam, gravel, and sand like that of river-deposits, neither 'gaps' nor 

 river-gravels can be detected. From its very nature, the district- 

 does not lend itself to the usual manner of treatment of river- 

 development questions. 



The Gipping Valley appears to be purely a consequent one, but 

 it is noteworthy that the watershed between the Gipping (or 

 Orwell) and the much smaller Deben is actually in the east of the 

 town of Ipswich, near the Asylum. Here the small tributary 

 valley which passes eastwards through Foxhall, Brightwell, etc., 

 originates. 



1 Davis, 1895 (15) p. 144. 



