1911] Fernald,— Expedition to Newfoundland 155 
made large progress, the ice-sheet had retreated to Canadian territory, 
excepting the portions left about the higher mountains of eastern 
and western America.” ! 
In 1908, the late John H. Sears,? accounting for the presence in 
Middlesex and Essex Counties of isolated southern plants, cited 
Dana’s discussion of the occurrence in Northumberland Strait and 
at other points north of Cape Cod of a southern mullosk fauna in 
which Dana had concluded that, since “none of the shells are found 
in elevated beaches; ...the migration from south of Cape Cod took 
place in the Recent period. Such a migration, extending to the St. 
Lawrence Gulf, was not possible, unless the Labrador current had 
first been turned aside; and a closing of the Straits of Belle Isle 
would have brought this about. This implies an elevation of about 
200 feet; and it may be that the rise which introduced the Recent 
period carried the continent, to the north, to this height above the 
present level. In the Champlain period of subsidence the Straits 
were open, this being proved by the cold-water shells of the now ele- 
vated beaches.” * And basing his conclusions in part on the presence 
of the southern plants — Echonodorus tenellus, Scirpus Hallii, Betula 
nigra, Magnolia virginiana, ete., in part on the occurrence in coastal 
muds of Essex County of southern invertebrates, Sears concluded 
that the southern flora (and fauna) reached northeastern Massachu- 
setts during the elevation which followed the Champlain subsidence. 
Thus, by Hollick’s interpretation, which was accepted by Dana 
(who placed their migration and that of the mullosks of North- 
umberland Straits at different times) the southern plants reached Cape 
Cod in “the period of Glacial emergence which made New Jersey, 
Staten Island, Long Island, with the islands east of it and southern 
New England, continuous dry land... .long before the alleged sub- 
sidence had completed its work” 4; while by Sears the time of the 
migration of the southern plants is placed after the Champlain subsi- 
ence. The final weighing of the more detailed geological evidence 
must of course be left in other hands, but it is possible that on the 
more general question we may gain some light by further investigating 
the origin of the southern flora of Newfoundland. 
oot Man. Geol. ed. 4, 980 (1894). 
-H. Sears: A Southern Flora and Fauna of Post-Pleistocene Age in Essex County, 
: usetts. Ruopora, x. 42-46 (1908). 
Dana, |. ¢. 995 
