OBSERVATIONS. 23 



southern of these two islands, as well as extend over it, just as they do in the 

 case of the northern, and so that, being bedded in the channel and up to the shore 

 of this southern island, they lie much below the level of the Chillesford beds 

 which cap it at Chillesford, Sudbourne, Iken, Oxford, and Aldboro', as well as below 

 much of the Coralline and Red Crag on which those beds there rest, and of which that 

 island is formed.^ Occupying also the channel dividing these islands from each other, 

 and in that way furnishing the section of Dunwich and Southwold Cliffs, these sands lie 

 up to the shore of the northern island thus formed of beds of Crag age, as may be seen 

 in the southern part of Easton Cliff when this is sufficiently free from talus. It is in 

 this part that a bed of shells occurs in these sands, and it is the only one, so far as I am 

 aware, that they yield in Suffolk. This shell bed is exposed at the northern end of 

 Southwold CUff, about the beach level, and immediately under the morainic loam already 

 mentioned -^ and I call attention to it because I believe that all the shells in it are 

 derivatives from the Crag of which this Lower Glacial island was formed, before the pro- 

 gress of the submergence overwhelmed it, in a similar way to that in which so large a part 

 of the shells in the Red Crag are derivatives from the island and peninsula of Coralline 

 Crag which existed in the Red Crag sea. Not only is the characteristic species of these 

 sands in Norfolk, Tellina Balthica, not present in this bed, but the shells that are in it, 

 even the strongest, such as the Littorinae, are for the most part fragmentary. The 

 shells which I was able to detect in it during many repeated searches were the 

 following, viz. Nassa incrassata^ Purpura lapillus^ Cerithium tricincium, Turritella 



1 The southern of the two islands mentioned in the text may have been divided into three smaller, by 

 channels now represented by the mouth of the Aide and by the Butley creek, in which these Lower Glacial 

 sands may have been bedded and since removed ; for at Iken Cliff, on the Aide, these sands are in section 

 at the sea level, nearly fifty feet below the contiguous top of the Chillesford beds on this island. This 

 southern island (or islands) was probably abutted on the south by another island formed of Red Crag, and 

 now buried beneath the Lower Glacial sand (capped with more or less of the Middle Glacial gravel) of the 

 heaths of Hollesley, Boyton, Sutton, and Alderton ; for exposures of Red Crag along the edges of the small 

 valleys penetrating this tract of country occur at as high or even higher level than the Chillesford beds 

 just referred to. This, again, was probably divided by a channel now represented by the Deben from 

 another island of Red Crag, represented by the tract between the Deben and Orwell estuaries, and this 

 again by one represented by the tract between the Orwell and Stour estuaries ; as from the way in which 

 the Lower Glacial sands take the place of the Crag in many parts along the sides of the valleys of these 

 estuaries, these latter may very likely have been channels during the earlier part of the Lower Glacial sea, 

 and been once filled by its sands, which were removed by the action of the sea, followed up by the land 

 ice as the land was emerging during the formation of the chalky clay. Whether the Chillesford clay ever 

 was spread out over that part of the Red Crag which occupies the area between Butley and the Stour, and 

 was afterwards removed, or whether this southern part of the Red Crag was land during the slight depres- 

 sion under which the Chillesford beds were spread out, there are no means of determining, though the 

 Chillesford clay seems to have been deposited in north-east Essex (Walton), and up the Gipping valley at 

 Needham. 



~ This bed was also found about half a mile inland in making the railway cutting near Southward 

 station. 



