358 H. H. Howorth—A Great Post-Glacial Flood. 
angles intact, the former have long been recognized as the débris of 
disintegrated Tertiary pebble beds. Searles V. Wood, Murchison, and 
others who have written so much on these beds are quite agreed 
about this. 
The pebble beds of Budleigh Salterton have recently been shown to 
have been the matrix from which many of the pebbles of the gravels 
of Central England were derived. 
Again, Mr. Mackintosh says, “South and South-east of the Wrekin 
and Ashley water-parting (as well as round the water-parting itself) 
there are extensive Triassic pebble beds which have been broken up 
and redistributed in a South and South-east direction, probably for 
the most part by oceanic currents and waves; for it would be un- 
reasonable to suppose that all the great, and often continuous spreads 
of pebbles could have been uprooted and transported by floating ice ” 
(Journ. Geol. Soc. vol. xxxvi. p. 182). 
Mr. H. B. Woodward in a letter to Mr. Belt, in which he refers 
to the gravels on the Black Down Hills, says, “The occurrence of 
old pebbles in a clayey drift on the tops of the Greensand heights is 
the most important, because, on the Paleeozoic rocks of Devonshire, it 
is often very difficult to decide between a drift gravel and the dis- 
integrated conglomerates of the New Red Series” (Journ. Geol. Soc. 
vol. Xxxil. p. 82). 
If these conclusions he just, it enables us to reconcile the presence 
of great beds of water-worn pebbles with the complete absence of 
subaqueous débris, especially shells; for we can see at once that if the 
materials of these beds have been entirely re-sorted and are derivative, 
their more fragile contents have either been destroyed or sifted 
out in the process, and we have only the more resisting elements left, 
and we can most reasonably conclude that, except in the case of those 
beds bordering on the sea which contain marine shells in a broken 
condition, the rest of the gravels with rounded pebbles in all pro- 
bability are the redistributed remains of gravels or pebble beds 
which previously existed on the land, and in their present position 
and distribution in no way evidence the recent position and distribu- 
tion of the sea or of masses of freshwater. Having settleds this, 
let us now consider more closely the mode in which these gravels 
are distributed. For this purpose we must enter somewhat more into - 
detail. 
It is the fashion to class most of the gravels and sands we are dealing 
with, with the Boulder-clay and other Glacial deposits. This view I 
cannot at all accept; but, on the contrary, I hold that they should 
be completely separated. When, in 1865, Mr. Hull published his 
paper on the arrangement of the Lancashire Drift deposits, in the 
Memoirs of the Lit. and Phil. Soc. of Manchester, separating them 
into three divisions, a lower Boulder-clay, surmounted by gravels 
and sands, and these again by a second Boulder-clay, he started a 
discussion which is still undecided. I venture to think that it will not 
be decided in favour of the propounder of the theory. That this 
tripartite classification holds good for certain very limited localities 
in Lancashire, Yorkshire, and for others in Wales, is true enough ; 
