PRELIMINARY LIST OF THE MAMMALS OF NEW YORK 289 
ing is removed boreal species disappear, while their places are taken 
by austral forms. Instances of this process in New York have been 
citeday by + Millen €o3byepy 163), and) Meamsie(g8b.eep. 3425) 93455, 
360). The observations of the former refer to the rapid replacement 
of the Canadian white footed mouse, -eromyscus canadensis, by its 
more southerly reiative, P. leucopus noveboracensis. Mearns says: “ The 
interior region of the Catskills surrounding Kaaterskill Junction belongs, 
as a whole, to the Canadian, the lowest of the boreal faunae, though 
slightly mixed with the Alleghanian [transition] in the farming lands on 
the banks of Schoharie creek. There is some evidence, however, that 
certain mammals of the transition and upper austral zones, as the 
New England cottontail (Lepus sylvaticus transitionalis), deer mouse 
(Peromyscus leucopus), and gray fox (Urocyon cinereoargenteus), have but 
lately extended their ranges to this locality by following up the clearings. ” 
The explanation of the climatic changes that induce this alteration in 
fauna would involve a more thorough knowledge of forest influence 
than is now available. Much could be done toward a solution of the 
problem by a thorough biologic and climatologic survey of a small 
Canadian area on the southern edge of the Adirondacks. After the 
normal conditions under which the Canadian fauna existed were well 
understood the area should be cleared and reduced to the condition of 
a brushy pasture. This would give opportunity for a duplicate set of 
observations after the change in fauna had taken place, and from a com- 
parison of the two sets, important conclusions would undoubtedly be 
reached. © 
Upper austral zone. ‘The upper austral zone enters New York in 
two widely separated regions, the Hudson valley, and the extreme 
western part of the state in the “lake region.” 
In addition to the southern species already mentioned as extending 
their ranges into the transition zone the strictly characteristic mammals 
of the austral zone are: 
Didelphis virginiana opossum 
Lamias striatus striatus southeastern chipmunk 
Feromyscus leucopus leucopus southeastern white-footed mouse 
LVeotoma pennsylvanica\ cave rat 
Lepus floridanus mallurus southeastern cottontail 
Urocyon cinereoargenteus gray fox 
Fipistrellus subflavus subfiavus Georgia bat 
fipistrellus subjlavus obscurus' dusky bat 
1 Phe faunal position of-thisweatis not positively known. 
