492 S. V. Wood,jun. — American and British Surface- Geologtj. 
extent, of wbich I consider tbe English formations to afford evidence. 
Prof. Newberry, bowever, observes tbat most. of tbe forest inter- 
vening between tbe Erie clay and tbe beds 3a was Coniferous, and 
tbat as it ineludes tbe Cedar and Cranberry, it may be regarded as 
indicating a climate somewbat colder tban tbe present ; for it is not 
clear tbat tbe forest-beds wbicb yield so many of tbe plants wbicb 
still grow in tbe same localities, and wbicb could not have grown 
if tbe climate bad been rnucb colder, are of tbe same age as are tbose 
lound intervening between tbe Erie clay and tbe beds 3a. 1 
It sbould, bowever, be borne in mind tbat if tbe forest-beds thus 
intervening be in sitü, a great amelioration must, it seems to me, 
bave ensued ; for unless tbe ice bad completely tbawed out of tbe 
lower valley of tbe St. Lawrence, wbicb lies in several degrees 
bigber latitude tban Ohio, tbe lake-basin could not bave been laid dry 
so as to Support a forest growtb ; because an amelioration sufficient 
only to release tbe Obio portion of tbe basin from tbe glacier-ice 
indicated by tbe Erie clay, and by tbe striated surface down to 
latitude 39°, would bave only brougbt about tbose conditions wbicb 
are described by Prof. Newberry as giving rise to tbe beds 3a, and 
wbich I bave attributed to tbe return of a minor glaciation ; viz. tbe 
filling of tbe Obio lake-basin witb fresbwater instead of tbe for- 
mation of a land-surface. Moreover, bow could tbe lake-basin bave 
again become filled witb fresbwater after a land-surface, unless a 
return of glacial conditions took place, minor in degree, but sufficient 
to dam up tbe lower valley of tbe St. Lawrence witb ice ? 
Wbatever may prove to be tbe case, bowever, as to the nature of 
tbe terrestrial climate wbicb preceded tbe minor glaciation, I tbink 
tbat we bave in some parts of North-Westem Europe evidences of a 
warmer marine climate during a very late geological period, tban 
tbat wbicb now exists in tbe same region as specified in tbe sequel. 
Besides tbe beds 3a, Prof. Newberry describes certain gravels forrn- 
ing bills and mounds upon tbe water-parting wbicb in Obio divides 
tbe drainage flowing to tbe St. Lawrence from tbat flowing to tbe 
Mississippi. Tbese gravels, wbicb, in Order not to dissever tbem from 
Prof. Newberry ’s sequence of deposits, we will call 36, be regards as 
similar to Karnes and Eskers as tbey are called in Scotland and Ire- 
land ; and tbey are attributed by bim to tbe action of shore- waves 
among low islands and sballows, in wbicb condition tbe bighlands 
of Obio were at the time when, during tbe formation of the clays 
witb boulders (3a), North America underwent, be considers, a sub- 
mergence so great tbat tbe sea overflowed tbe water-parting between 
the St. Lawrence and Mississippi basins. 
I am unable, bowever, to understand wby, if tbe sea overflowed 
1 It must not be, bowever, forgotten tbat the doubts wbicb are being raised as to 
whether the Forest-bed of the Norfolk eoast is in sitü apply witb greater reason to 
the forest-beds over tbe Erie clay wbich appear to have been only encountered in 
sinkings, and therefore not open to so rigorous an examination as the Norfolk forest ; 
so that if the latter should turn out to be a land-surface ploughed off and removed 
bv the agency of ice, it would be difficult to resist a similar explanation for the Ohio 
forest-bed ; and in such case the beds 3a would probably prove to be only a con- 
tinuation of the Erie clay formation itself. 
