FAUNA OF THE SOUTHERN ALLEGHANIES. 393 
fessors Verrill* and Agassizt to faunal associations of spe- 
cies of animals, characteristic of Canada and. adjacent 
territory, and the Middle and Eastern United States, etc. 
The former author, in the later essay quoted, attempts to 
define these faune in a more or less precise manner, regard- 
ing the southern boundary of the first as “coincident with a 
line which shall indicate a mean temperature of 50° Fahren- 
heit, and the southern boundary of the second, to be the 
line of 559." In accordance with this view the southern 
boundary of the Canadian fauna, commencing at the mouth 
of the Penobscot River in Maine, extends parallel with the 
coast into New Brunswick, and returning through middle 
Maine passes south of Moosehead Lake and the White 
Mountains, along the eastern base of the Green Mountains 
to the south, and up their western foot to the river St. Law- 
rence. From near Montreal it turns to the south-west, and, 
passing through Lake Ontario, crosses Michigan from St. 
Clair to Milwaukee, and rises following the valley of the 
Mississippi northwards. The Adirondack Mountains were 
regarded as a portion of this fauna, surrounded, like an 
island, by the Alleghanian. 
The southern boundary of the Alleghanian was traced 
from near Norfolk, Virginia, up the valley of the James 
River to the Alleghany Mountains, southward along their 
base to their termination in Georgia, and then north again 
along their western slope to Kentucky and the Ohio River. 
The Southern, or Louisianian, fauna included the lower por- 
tion of the Ohio basin, and an undetermined extent of that 
of the Mississippi north of the latter. The boundary line 
then descended to the south to the west of that river. I 
may suggest here that the most northern habitat of the Siren 
lacertina might prove to be near the northern extreme of the 
boundary in question. This point, so far as I am aware, is 
* Proceedings Essex Institute, III. 136. Proceedings Boston Society of Natural His- 
Ty, 1866, . 
t Nott and Gliddon, “Types of Mankind,” 1853. 
AMER. NATURALIST, VOL. I. 50 
