S. V. Wood,jun. — American and British Surf ace-Geology. 541 
Tlie Middle and Upper Glacial deposits of England appear to me 
to have been formed dui'ing the culmination and recession of the ice 
only, as in the case of the Kames of the Ohio water-parting and of 
the Erie clay. Düring the accumulation of the Middle Glacial sand 
and gravel formation, it is not clear how far the ice extended, 
because, by the action of the inland ice on the westem side of the 
three Eastem counties, after the elevation of the greater part of 
them into land which accompanied the protrusion of glacier tongues 
along their valleys, as presently explained, this formation on the 
■westem sides of these counties seems to have been destroyed. The 
origin of these sands and gravels, however, appears to have been due 
to the washing out hy submarine currents of the moraine extruded 
by the land-ice lying somewhere west of the line marking this 
destruction in Suffolk and Norfolk which is defined in the sequel ; 1 
and this was both accompanied and followed by the lifting and 
dropping through the agency of floating-ice of sheets of the un- 
stratified moraine itself, because we find such moraine occasionally 
interstratified in the sands and gravels, as well as very extensively 
forming a thick bed of Glacial clay over them. 
Düring the first formation of these sands and gravels, the eastem 
side of England must have been submerged some 400 feet, because 
we find them (without any indication of disturbance having occurred 
in the floor which supports them) ranging from the present sea- 
level nearly up to that altitude. Near the Southern extremity of 
Glacial clay occurrence in Middlesex, these gravels ränge up to 
about 300 feet at Finchley, where they are covered by the morainic 
clay, and in Essex to 367 feet at Danbury, where they are not so 
covered. Between these points the morainic clay of the Upper 
Glacial occupies for the most part lower ground, resting direct on the 
London clay, as though, after the deposit of the sands and gravels, 
and their partial overspread by the morainic clay dropped upon them, 
the ice had advanced and ploughed out the lower ground, which was 
afterwards covered by the moraine extruded. 2 
The distribution of the same sands and gravels and of the 
morainic clay over parts of the counties of Hertford, Bedford, 
Buckingham, Warwick, Oxford, and Leicester, where in some in- 
stances they attain elevations somewhat greater than at Danbury, 
discloses analogous features ; and seems to indicate that similar 
small extensions and recessions of the ice when at its furthest limit 
took place in that part of England also. 
As the sands and gravels with marine mollusca reach in North 
Wales to an elevation considerably exceeding 1300 feet, and in 
Lancashire, on the west slope of the Pennine ridge, to elevations 
1 A considerable spread of coarse rolled flint gravel in "West Norfolk resembling 
cannon shot seems to have resulted from similar current action during the formation 
of the Upper Glacial chalkv clay, upon which in some instanees it seems to rest. 
2 The position of the beds thus referred to is shown in the Geological represen- 
tation of Ordnance Sheets 1 and 2, which I made, and in the year 1866 placed in the 
Library of the Geological Society, with a manuscript memoir and sections in illus- 
tration of it. It is also shown in the map at p. 348 of Yol. III. Geol. Mag. 1866. 
