456 Sir II. II. Hoicorth— 



This view has been partially urged by Prestwich, and notably 

 by Monckton, Herries, and the other younger geologists who have 

 done so much to unravel the history of the Southern gravels. 

 I would merely press their conclusions further, and affirm that all 

 the rolled and rounded pehbles in the so-called Glacial clays and 

 gravels are derivative, and have been derived from earlier Tertiary 

 beds. I shall have more to say of them in a subsequent paper 

 on the gravels and sands so frequently associated with the clays. 



Turning from the polished pebbles to the angular and suhangular 

 rubble of home-made rocks, this consists of various kinds of 

 Secondary strata, Lias, Oolite, and Chalk, distributed generally with 

 a preponderance of Lias, Oolite, and Chalk fragments when the 

 underlying beds correspond. These fragments, which have been 

 partially shifted, and rolled and rubbed against each other, are, as 

 I have tried to argue in two recent papers in the Geological 

 Magazine, the result entirely of the violent dislocation of the 

 local Lias, Oolite, and Chalk solid beds, which has broken them 

 up sometimes into great masses, and at others into mere road- 

 metal. This disintegrated rubble was, in my view, ready made 

 when the clay was compounded, and was in a large measure in situ; 

 and the only alteration it underwent at the time when it was put 

 into the portentous churn which turned out the chalky and other 

 clays of Eastern England, was to have its angles blunted and its 

 sides scratched and polished by being rolled and rubbed together. 

 This seems as plain as plain can be if we are to explain the facts 

 by inductive methods. 



Whatever the forces or the machinery which mixed and dis- 

 tributed the so-called Boulder-clays of Eastern England, they had 

 nothing to do with shaping the home-grown ingredients of the 

 clays. These, with the exception of a little blunting of angles 

 and polishing and some scratching, were already made, and are 

 derivative. The process we have to analyze, therefore, is not 

 complicated by questions as to the modus operandi by which the 

 matrix of the clay itself and its contents were formed, but is 

 limited to an explanation of how these ingredients were mixed 

 and mingled together as we find them ; and, secondly, how the 

 product, when mixed, was distributed. What is most plain, 

 in limine, is that, as the matrix of the clay and nine- tenths of its 

 contents are local, it was fashioned on the spot, and was not im- 

 ported. This follows from another fact. I have examined the coast 

 of Norfolk and Suffolk with some care, and in those counties, 

 as I have said, the Chalky CLiy never reaches the sea, but 

 occupies the projecting bluffs that form the highlands a few miles 

 inland, while the country between them and the sea is occupied by 

 the pebbly beds; the same is the case in Essex. This makes it clear 

 that the Chalky Clay, which occupies the larger part of the interior 

 of those counties, did not move westward from the seaboard, but 

 came from the north or north-west, whence the chalk fragments 

 and the clay itself were derived. This is again shown by the fact 

 that this clay in Suffolk contains so mauy Liassic fossils. What is 



