198 Part III. Chapter 2. 
Arbitrarily considered, all of the territöry above this line and between it and 
the great terminal moraine was a country influenced by the glacial cold where 
tundra conditions prevailed. All of the country south of it, protected by the 
Alleghany Mountains, was covered by a forest composed in the main of those 
species of trees, not destroyed by the glacial cold, that had existed in this 
region, and also in the far north, prior to the advent of the last glacial epoch. 
Comparing the northern remnant of the magnificent Tertiary forest with the 
southern remnant of this forest in the region drained by the Tennessee River 
and its tributaries and in the southern Appalachian Mountains, generally spea- 
king, it lacked many of the peculiar arboreous and herbaceous species which 
characterize the flora of the south and many of which peculiar plants have 
their nearest living representatives in the flora of eastern China and Japan’). 
North Carolina. These facts argue for a great antiquity of the flora 
of the mountains of western North Carolina. The presence of so many peculiar 
types of plants, not found elsewhere in America and having their closest 
relatives in eastern Asia, makes it more certain that groups, now broken up 
and detached, were once more continuous, and that fragmentary groups and 
isolated forms are but relics of wide-spread types, which have been preserved 
in a few localities where the physical conditions were especially favorable. 
This important principle is evidenced on every hand, as a botanist travels 
through western North Carolina”). The large size of the trees, the close com- 
mingling in a dense forest of a great variety of species,. the graded-down 
appearance of the land surface, and the rounded contour of the mountains, all 
impress the fact upon him that the country through which he travels has been 
subjected through long ages to the continued action of climatic forces which 
have carved the land into its present form and influenced the character of the 
vegetal covering. | 
In the Ohio Valley, the streams flowing from the south during the glacial 
period would aid in preserving the broad-leaved mesophytes, as far north, as 
the Ohio River. It is probable that in the interior the Ohio basin was occupied 
by the oaks, ash, hickories, elms and maples. Judging by the present northern 
limits of some of these species it is doubtful if the conifers could compete 
with them at any great distance from the ice front, so that the belt of tundra 
and conifers may have extended, as far south, as the Ohio, but it seems 
probable that even north of this river species of oak, ash, elm and maple 
persisted®). Beyond the Mississippi, the conditions must have resembled those 
now prevalent in the Saskatchewan basin. 
1) HARSHBERGER, J. W.: A phyto-geographic Sketch of extreme southeastern Pennsylvania 
Bulletin Torrey Botanical Club XXXI: 125—159. Mch. 1904. 
2) HARSHBERGER, J. W.: An ecologie study of the Flora of mountainous North Carolina. 
Botanical Gazette XXXVI: 255. Oct. 1903. 
3) Bert, ROBERT: The geographical Distribution of the forest Trees in Canada. Scottish 
Geographical Magazine XIII: 281. 
