98 THE AMERICAN NATURALIST. [Vor. XXXV. 
liable to ameliorate the climate which in the adjoining coun- 
tries cannot have been much different from that of Baffin 
Land. This conception is of course widely different from an 
absolutely unbroken ice sheet with a temperature destructive 
of all higher life, but it is also greatly different from the idea 
of Dr. Scharff. Moreover, it is not inconsistent with a possi- 
bility of even a considerable number of southern forms having 
survived the glacial period in various sheltered nooks and 
corners. The humming bird occurs even as far as Sitka, 
almost in sight of the gigantic glaciers, and forests are known 
to grow above a substratum of ice. The Lusitanian species 
in Ireland may well have survived the glacial period, even 
including the spotted slug (Geomalacus maculosus). The fact 
that it occurs in Cork and Kerry Counties of Ireland to-day 
does not prove that it lived there throughout the glacial period, 
and that consequently the glacial climate was mild or milder 
than now, for on page 156 Dr. Scharff has a chart showing 
Ireland to have extended probably a couple of hundred miles 
farther south, this extension forming a large peninsula which 
must have been washed on both sides by comparatively warm 
currents. It is quite possible that the more tender species of 
the Lusitanian fauna enjoyed here a congenial climate during 
the greatest glaciation, retreating to their present stations in 
Ireland as the sea rose and the glaciers receded. It is therefore 
scarcely necessary to postulate a temperate climate for Europe 
during glacial times. Not only did considerable changes of 
the climate take place during that period over large areas, but 
there must of necessity also have been a great variation inside 
this vast area according to local conditions, while in the adja- 
cent countries not directly subjected to the glaciation these 
local variations must have been vastly greater. We see even 
to-day isolated spots having a southern temperature within the 
limits of countries with a northern climate, and on the other 
hand similar northern oases in regions bounded by isotherms 
indicating a southern climate. 
One of the principal reasons which has led Dr. Scharff to 
assume such a mild climate in Europe at that time is the 
mixture of southern and northern forms in several deposits. 
