the Ujyper and Lower Drift of the Eastern Counties. 405 



which result from the regular and constant interniixtare of the 

 fresh water of rivers with the sea-water. This conjecture also 

 receives some support from the circumstance that the included 

 shells of the Loess appear to become rarer as the distance from 

 the Rhine increases, and from the fact that the Hesbayan mud, 

 argillaceo-sandy in Belgium, becomes on the extreme east of 

 Suffolk more clayey, but yet less so than further to the west, and 

 its included chalk debris are there but scanty; while as we go west- 

 ward, and approach the region of the oolitic clays, from which so 

 much of the argillaceous material of the Boulder-clay of the east 

 of England has been derived, the clayey character of the deposit 

 becomes more decided. Approaching the Chalk region, as 

 well as over it, the extensive intermixture of chalk-detritus 

 shows that the adjacent material largely contributed to the 

 sediment, and that little or nothing was derived from the Hes- 

 bayan area. Over the Eastern Counties also the Boulder-clay 

 is destitute, so far as hitherto observed, of fossils ; so that it 

 would seem to form a sort of neutral ground between the Loess 

 with its included land-shells, and the Boulder-clay of the north 

 with its deposits of marine shells. 



I have not been able to find any description of the upper 

 Crag of Antwerp calculated to throw any light on the relation- 

 ship borne by that deposit to the Campinian sands, or showing 

 whether the transition that exists in Suffolk between the Red 

 Crag and the lower Drift obtains also in Belgium ; and, indeed, 

 it would seem that the level state of the country around Ant- 

 werp forms an obstacle to a satisfactory investigation of that 

 question. 



****** 



In the paper on the " Red Crag and Drift " {'Annals,' March, 

 p. 185) I observed, in reference to the passage-beds between the 

 Red Crag and Drift, that I understood from Mr. Prestwich that 

 he no longer adhered to the section of that place published by him 

 in the Quart. Journ. Geol. Soc. (vol. v. p. 345). I, however, 

 should have said that it was his interpretation of some parts 

 of that section, and not the order of superposition, to which 

 Mr. Prestwich does not now adhere. It will be seen, by a 

 comparison of the two sections, that, in point of superposition, 

 there is no material difference between them. It was in respect 

 of the unconformability of these beds to the Red Crag that 

 ray views differed from those expressed by Mr. Prestwich in 

 1849. 



