INTRODUCTION. xxi 



belonging to the Middle Glacial formation, it is not impossible that the lower part of 

 them, which is sometimes very red, may belong to the pebbly sand, No. 6 ; but no means 

 occur to us by which that could be determined, the whole sand mass presenting no line 

 of division, and being unfossiliferous alike. It is easy, however, to see that they have no 

 connection with the Red Crag, for along the north side of the Stour and south side of the 

 Orwell, this Crag occurs only in places under them, the sands there resting for the most 

 part on the London clay. Moreover did any part of the sands covering the Crag belong 

 to that formation, it would be to the Chillesford beds, which overlie the Red Crag to the 

 north at Chillesford, and to the south at Walton. Over the greater part of the Red 

 Crag area, however, no trace of the Chillesford clay appears in the numerous deep sections 

 of sand with this Crag at their base, which there occur. The Red Crag has, evidently 

 prior to the Middle Glacial, been denuded of some of its upper part, even over the 

 country east of the Deben, since the Scrobicularia beds, which, by losing upwards 

 their oblique stratification, indicate an increased depth of water which must have carried 

 them over the Crags of Butley, Capel, Boyton, &c, do not occur south or west of 

 Chillesford. Between the Deben and the Orwell this denudation has been greater, 

 for at one point, north-west of N acton, the Middle Glacial has for an interval of three 

 miles no Crag under it ; while between the Orwell and the Stour, and across the Stour 

 towards Harwich and Walton, only small patches of Crag occur at intervals under the 

 Middle Glacial, that formation for the most part resting direct on the London clay ; and 

 sometimes, as at Wrabness, only the phosphatic nodule bed has escaped. As the 

 Chillesford beds, which must once have spread from Walton Cliff northwards over the Red 

 Crag, have for the most part 1 gone with it, this denudation must have been 

 posterior to them, and most probably was the same as that which intervened between the 

 contorted drift and the Middle Glacial in Norfolk, as the two (apparent) outliers of the 



BUGGED SUEPACE OP OBLIQUE EED CEAG ENVELOPED IN MIDDLE GLACIAL SAND IN A 

 PIT A QUAETEE OP A MILE S.W. OP MELTON CHUECH, NEAE WOODBEIDGE. 



The dark oblique bedded mass is the Crag. 



1 There may of course be patches of these beds over the Red Crag between the Stour and the Aide, which, 

 for want of sections, are not shown on the map, and are lost in the expanse of Middle Glacial sand. 



