440 Mr PHEAR, ON THE GEOLOGY OF SOME PARTS OF SUFFOLK, 



The foregoing are the most prominent details of the information which I have been able 

 to gather for myself with regard to the geological phenomena of the Gipping valley: they 

 seem capable of being very concisely summed up : 



The upper part of the valley and its branches is channelled in the drift-clay, from Need- 

 ham to about Bramford in the chalk, and the remaining portion, including the Orwell itself, 

 in the London clay. It is fringed at a high level on both sides, at least between Ipswich and 

 Needham, with a line of sand-cliffs. At Stoke, the easterly end, this sand overflows, as it 

 were, the edge of the valley, and forms the light lands of the higher grounds between the 

 Stour and Orwell estuaries: indeed it is not improbable that the sandy heaths, which cover 

 the whole coast-district of the county from Saxmundam to Harwich, and thence extend into 

 Essex, may be continuations of the same. If the prolongation of the same cliffs in the 

 opposite or N. W. direction is less distinctly marked beyond the limits of the chalk, it is still 

 extended far enough to cover the drift-clay at Creeting (p. 435), and thus to suggest very 

 strongly its identity with the patches along the Stonham valley : it is in one (p. 437 Hill-farm) 

 of these latter only that I have found any fossils in situ; they are very ill preserved, but 

 Prof. M c Coy has pronounced some of them to be recent. 



The question now offers itself, what is the proper relative position of this sand ? is it the 

 sand upon which (as will be afterwards mentioned) the drift-clay always seems to rest, exposed 

 by the depth of the valley sections, or is it merely the edge of a mass which once filled the 

 whole breadth of the valley and has since been swept away by denudation ? 



The first hypothesis is that which most naturally suggests itself, and I confess that I 

 cannot with any satisfaction dismiss it ; but on the other hand the results of my observa- 

 tions do not at all encourage me to hold it. The circumstances, which appear to me incon- 

 sistent with it, are : 1st, that the clay is nowhere seen to rest upon this sand ; had it ever 

 been above it, the probabilities are that it would have been left by the denuding cause, at 

 some spots at least, throughout the many miles of sand-ridge in the shape of a sharply- 

 defined cap ; but the fact is, that it appears nowhere in an immediately superior position, 

 and where it does manifest itself close in the rear of the sand, its thickness is not percep- 

 tibly less than at remoter distances : 2ndly, that at Creeting (p. 437) if the sand is not exhibited 

 actually resting upon the clay, it is above it and in contact with it in several directions : 

 3rdly, that the gravels and coarse sands bear every appearance of being due to the destruction 

 of the clay itself : 4thly, that these gravels and coarse sands with some immediately underlying 

 laminae of fine clay invariably cap the sands in question, while nothing of the kind occurs 

 between the drift-clay, and its underlying sand. 



It may be added that in the Stonham valley the sands are undoubtedly resting in more 

 than one place upon the drift-clay, and they resemble in regularity of stratification and every 

 other characteristic those just alluded to : this circumstance strongly suggests their being 

 continuous with the ridge, and therefore supports the second view. 



The section of the Stowmarket well (p. 439) no doubt complicates the case, as its sand 

 with recent shells greatly resembling the sand of the Stonham valley (p. 437), lies between a 

 so-called drift-clay and the chalk ; but may not this clay " with lumps of chalk" be recon- 

 structed drift ? that which is worked in the brick-yard at the head of the town most 



