116 H. H. Howorth—Traces of a Great Post-Glacial Flood. 
same throughout, but have, in the middle beds, unstratified clay, 
silt, and muddy gravel, while the upper and lower strata consist of 
clean sand and water-worn shingle, evenly stratified and without 
any trace of mud. The same conclusion seems to follow from the 
fragmentary and sporadic character of the patches of drift which 
seem to point to some powerful denuding agency, such as a current 
of water on a large scale since their deposition. “It is impossible,” 
says Mr. Maw, “to compare the numerous outlying patches of drift, 
the various levels at which they occur, and the great individual 
thickness of some of the isolated patches, without being convinced of 
the large proportion that has been removed, compared with what 
remains” (id. p. 142). 
Speaking of some of these drift beds, he says, “‘ At the height of 
60 or 70 feet above the river, and about 165 feet above the sea, 
these clean sand beds are replaced by a most heterogeneous mass of 
drift, in which stratification is almost absent: they are about 60 feet 
thick, and included within the top and bottom of the railway cut- 
tings. So singularly various is their aspect, and so obvious in 
irregularity and variety of structure and materials, as to call forth 
the remark from one of the navvies that ‘he had cut through plenty 
of hills in his time, but that he had never seen a hill with such a 
many kinds of muck in it as this.’ The transition from the sand 
beds is well marked and sudden, and the beds immediately suc- 
ceeding them consist of muddy subangular gravel, irregularly stra- 
tified, and containing beds of silt, drift coal and clay, irregularly 
disposed ; and also, in common with nearly the whole mass of drift, 
rocks and stones of various sizes and from many formations, a list of 
which is given below. The middle of this heterogeneous stratum 
consists of a mass of very tough unstratified clay, containing frag- 
ments of Wenlock shale, waterworn and subangular boulders, pieces 
of flint, and patches of curiously contorted sand and silt, the struc- 
ture of which is very similar to that of the strata at St. Acheul 
engraved at page 188 of ‘The Antiquity of Man’; they seem to have 
been subjected to continual moving, washing, and changing, from 
constantly varying currents cutting fresh channels and redepositing 
the materials.” 
Whichever way we view these Severn Valley marine beds, we seem 
to be forced to the conclusion that they are not the remains of an 
old sea-bottom, but the result of some transient movement which 
transported them from elsewhere. 
The present distribution of marine terraces points the same moral. 
If the land had been subject to secular movements of upheaval and 
subsidence on a large scale, they ought to be on a tolerably uniform 
level. As Mr. Jamieson says in a very recent number of this 
Macazine in reference to a very different theory, “The facts indicate 
avery unequal amount of submergence in places situated in the 
same latitude. The best-known high-lying marine beds of New 
England and Canada lie between lat. 44° and 52°, which corresponds 
to that of France and the South of England, just where evidence 
of submergence is conspicuous by its absence. Again, we find in 
