556 Rev. E. Hill — The East Anglian Bouldev-clay. 



afterwards. If the stone and the clay were deposited together, and 

 deposited by water, the appearance is intelligible. The natural ex- 

 planation is that the Boulder-clay was deposited in water, and that 

 ice, floating over this water, carried stones and dropped them. 



The clay is found in West Suffolk up to heights of 340 feet ; but 

 none of the neighbouring outcrops of chalk reach 300 feet, I have 

 attempted to trace the contour-line of 300 feet from the Tees to 

 the Thames. The tracing shows that chalky Boulder-clay in East 

 Anglia attains a higher level than any ground northwards up to the 

 Lincolnshire Wolds. Even there, the elevated area of chalk is 

 smaller than the equally elevated area of East Anglian clay. Be- 

 sides, Mr. Deeley tells us that chalk-drift is found in Leicestershire 

 up to 800 feet, which is far higher than any Northern chalk. It 

 seems, therefore, natural to suppose that much chalk country was 

 then relatively higher than now ; accordingly that a tilt of the 

 surface has taken place since Glacial times.^ This is similar to 

 a conclusion which Prof. Prestwich arrived at, on the independent 

 evidence of his Westleton beds. 



Another observation of mine may have a significance. In some 

 brickyards a coarse clay is ground up with water and allowed to 

 settle in shallow pits. A similar material is pi'oduced in Cambridge- 

 shire when the mud, washed off from coprolites, has been run into 

 the 'slurries.' When I have seen these pits cut into, their material 

 in its texture has sometimes strongly recalled to me some of the 

 finer varieties of Boulder-clay — for instance, the chocolate-coloured 

 clay of Holderness. This likeness suggests that the deposition of 

 Boulder-clay was a process which went on rapidly. If so, the 

 formation may have taken place in less time than we are accustomed 

 to suppose. 



The above observations, then, taken together, suggest the picture 

 of a broad sheet of water surrounded by slopes of clay and scarps 

 of chalk. . These are to be broken and pulverized by winter-frosts, 

 and washed down in muddy torrents by spring or summer rains, 

 while stones embedded in ice are also carried down, scratched in the 

 transit, and floated far before they are dropped. But the surface of 

 these waters cannot be still, nor even flowing in a uniform direction. 

 There must be tides, eddies, or varying winds, since something 

 seems required to drift the ice-rafts across the movement of the 

 muddy waters, so as to produce the mixture of materials which 

 we find. 



I have confined myself to my own area and my own observations; 

 also I have made no attempt to answer the ditficulties which may be 

 raised. There are, however, two obvious objections on which some- 

 thing may be said. It is urged that if the Boulder-clay be of 

 aqueous origin, it ought to contain fossils and be stratified. If my 



1 This argument of course assumes tlie conclusions preA'iously arrived at. Those 

 who maintain glacier-transport should bear iu mind that, unless levels have changed, 

 the ice must have been at a yet higher level above the spot whence it brought the 

 chalk. If this came, for instance, from Speeton, Fiamborough Head must then 

 have been buried beneath 500 feet of ice. 



