540 S. V. Wood,jun. — American and British Surface- Geolog jj. 
ance would liave caused, I conceive, the ice to seek a new direction, 
the result of wkich was tliat its main flow deflected more directly 
southwards from the Pennine Hills, and formed the large glacier sheet 
to wliich the Middle Glaciai sands and the chalky portion of the 
Upper Glaciai clay owe their origin, and of which the motion was 
partly out through the Humber gorge, but principally southwards 
over Lincolnshire. 
Since thus the earliest deposits of the Glaciai period in Britain 
belong to that part of it during which the ice was beginuing to 
accumulate and during which it was extending, but had not reached 
its culmination ; while according to Prof. Newberry the Erie clay 
belongs to that part of it during which it was receding, we can 
hardly suggest any parallelism iu time between this clay and the 
English Lower Glaciai beds, unless that part of the period which 
followed the elevation of the latter and the excavation of the 
troughs through them was accompanied by a general recession of 
the ice and amelioration of climate, as to which there does not 
appear at present to be any reliable evidence. On the whole, 
therefore, it seems to me most probable that none of the American 
beds, so far as they have yet been described, are quite so old as the 
Lower Glaciai series of England ; but that the oldest of them 
represent the period of recession from greatest ice extension under 
which the principal glaciai formation of Britain, the Upper Glaciai, 
was accumulated. 
As, however, the object of the present attempt at synchronism is 
tentative only, I have thought it most convenient to place the oldest 
described formations of either country side by side, as the clearer 
way of presenting the subject for the consideration of geologists, 
and therefore in pursuing that course we get next : 
England. 
St. Lawrence Basin. 
The Middle Glaciai sand and gravel. 
The Upper Glaciai beginuing with the Chalky 
clay of East Anglia, succeeding which comes the 
Purple clay of Holderness, and such of the clay 
of the North of England as is not of Hessle a ge, 
and terminating with the Moel Tryfaen and Lan- 
cashire high-level sands with marine mollusca. 
The Forest surface and asso- 
ciated beds (No. 2), which rest 
on the Erie clay. 
The beds 3« of Ohio and part 
of the marine clays of the 
Lower St. Lawrence and At- 
lantic coasts. 
If, as already suggested, there was no general recession of the ice 
and amelioration of climate after the formation of the Lower Glaciai 
series of England, and that therefore the Erie clay and Eskers of 
the Ohio water-parting more probably represent the Upper Glaciai 
of England, then the beds of the St. Lawrence hasin which are 
above placed beside the Middle and Upper Glaciai would, I conceive, 
belong to that period which we have been accustomed in England to 
call post-Glacial, and during which a minor glaciation, I consider, 
occurred ; and I tliink that this pushing forward of the American 
beds in the synchronism will eventually be found to accord best 
with the entire group of facts. 
