Mr. WhitaTier'' s Address to the Geological Section. 463 



sort seems to occur close to us, in the midst of the town of Ipswich, 

 where, by St. Peter's, one boring has pierced 70 feet of Drift, and 

 another 127, in ground but little above the sea-level. 



As the Drift sands and gravels, that in many places occur below 

 the Boulder-clay, often yield a fair amount of water, the proof of 

 their occurrence and of the thickness of the overlying clay is of some 

 practical good. 



The Crag. — On this geologic division we have a less amount of 

 information, as would be expected from the fact that it is not nearly 

 so widespread as the Drift, and this information is confined to the 

 Upper or Red Crag, the Lower or Coralline Crag occurring only 

 over a very small area, and no evidence of its underground extension 

 being given by wells. 



What we learn of the Red Crag, however, is of interest, several 

 wells having proved that it is far thicker underground than would 

 have been supposed from what is seen where its base crops out. 

 One characteristic, indeed, of this sandy deposit, in the many parts 

 where it can be seen from top to bottom, is its thinness, as in 

 such places it rarely reaches a thickness of 40 feet. But, on the 

 other hand, wells at Hoxne seem to prove more than 60 feet of 

 Crag, whilst at Saxmundham the formation is 100 feet thick, and at 

 Leiston and South wold over 140. Further north, just within the 

 border of Suffolk, there is, at Beccles, a thickness of 80 feet of sand, 

 01% with the overlying Chillesford Clay, a total of 95. Our under- 

 ground information has, then, trebled the known thickness of the 

 Upper Crag of Suffolk. 



It has also shown that at some depth underground the colour- 

 name is a misnomer, the shelly sands being light-coloured and not 

 red. This is the case, too, with some other deposits, which owe their 

 reddish-brown colour at the surface to peroxide of iron. Presumably 

 the iron-salt is in a lower state of oxidation until it comes within 

 reach of surface actions. This seems to point to the risk of taking 

 colour as the mark of a geologic formation. 



Eocene Tertiaries.— Below the Crag there is a great gap in the 

 geologic series, and we come to some of the lower of the Tertiary 

 formations, about which little had been published, as regards Suffolk, 

 befoi'e the work of the Geological Survey in the county. It seems 

 as if the special interest in the more local Crag had led observers to 

 neglect these beds, which had been amply noticed in other parts. 



We have records of more than forty wells in Suffolk that are 

 partly in these deposits, and of these thirty-six reach down to the 

 Chalk, twenty giving good sections from the London Clay to the 

 Chalk. The thickness of the Lower London Tertiaries (between 

 those formations) thus proved varies from 30 to 79^ feet, the higher 

 figure being much greater than anything shown at the outcrop. 

 The greatest recorded thickness is at Leiston, where, moreover, the 

 top 26 feet of the 79| may belong to the uppermost and most 

 local of the three divisions of the series, the Oldhaven Beds, of very 

 rare occui'rence in the county. The next greatest thickness is at 

 Southwold, where the whole has been classed as Reading Beds (the 



