306 BEV. E. HILL ON TRANSPORTED BOULDER CLAY. [May 1 896,. 



In the Willow Bridge pit the clay was 2 or 3 feet thick and extended 

 some 50 feet; whether continuously or in several adjacent masses 

 was uncertain : appearances were in favour of the latter view, but it 

 was difficult to decide on the nature of decomposed interruptions. 

 The outsides and the decomposed portions are a reddish clay or earth,, 

 but the cores are perfectly normal Chalky Boulder Clay, with much 

 chalk, in pieces from 2 or 3 inches long down to pea-size and grains. 



It seems impossible to suppose that the agent which produced the 

 Chalky Boulder Clay, after ceasing to operate during the long 

 interval indicated by the gravels, again set up work and produced 

 these scanty fragments. The pits described lie on the side of 

 Boulder Clay slopes which rise, though gently, to considerably 

 greater heights. A natural explanation is that the masses have 

 come from higher ground, floated off or slipping down, in either case 

 probably in a frozen state. Between them and the gravel lie seams 

 of a finer clay, and over them something of the nature of brick- 

 earth ; while brick-earth is also abundant and worked at nearly th« 

 same level midway between the two gravel-pits named. Under the 

 coarse gravel, in another of the pits, lie highly false-bedded white 

 gravel and sand. Thus there is abundant evidence of contemporary 

 water-action, and everything agrees with the view that these seams 

 of clay have been brought, not formed in situ. 



If these conclusions are established, some consequences follow. 

 The writers in the Survey Memoirs on East Anglia frequently 

 mention beds of Boulder Clay in unusual positions, intercalated in, 

 or overlying, sands and gravels. May not many of these be also 

 transported sheets ? If so, difficulties which the writers evidently 

 felt may be removed. Again, must not much caution be observed 

 in attributing an ' interglacial ' age to beds, fossils, or implements 

 found beneath thin sheets of Boulder Clay, especially where this 

 occurs also at higher elevations in the neighbourhood ? 



The Lowestoft instances would show that while in one locality 

 sands, called 'Mid-Glacial,' were being deposited, in some other 

 locality the manufacture of true Chalky Boulder Clay had already 

 been commenced and perfected, so that exportation could go on. I 

 do not see that they give any evidence of the process of manufacture. 

 They are not unlike the pieces which might break off from the clay- 

 banks of a Siberian river : — but I must not wander far into the field 

 of conjecture. 



Discussion. 



Mr. H. B. Woodward suggested that in Mr. Hill's Corton section 

 the Boulder Clay might occur in the form of an intrusive tongue ; 

 and in the West Suffolk section the isolated patches of Boulder Clay 

 might be remnants lying beneath a mass from which the chalky 

 portions had been removed by dissolution — a feature common in the 

 Eastern Counties. 



Prof. Bonney said that he had carefully examined the section south 

 of Yarmouth with Mr. Hill, and could not find the slightest evidence 

 of intrusion of the Boulder Clay — a thing, by the way, of which he 



