246 Dr J. B. Hurlburt on the Forests of North America. 
with many modifications, which, however interesting, as 
illustrating the effects of climate upon the flora of that con- 
tinent, it forms no part of the objects of this short paper to 
particularise ; but an example or two may be given. We 
have upon the White Mountains of New England an in- 
stance of the failure of all forest trees above an altitude of 
5000 feet. The summits of the Black Mountains of North 
Carolina, as the swartz wold, or black forest of the hills of 
Badan, are covered with balsam firs, and the shores of Hud- 
son Bay with low evergreen forests. In all such localities | 
the results are what the lower summer temperatures might 
have been expected to produce, as the higher temperatures 
of the coasts of the Gulf of Mexico and the Atlantic as far 
north as Virginia have caused other varieties of forest trees, 
such as the evergreen oaks, magnolias, palms, cypress, giant 
laurels, wild orange, satinwood, mahogany, and mangroves. 
The principal trees of these great mixed forests are of 
the Deciduous kind—the maple (Acer saccharinum and A. 
dasycarpum), the beech, the elm, ash, oaks, basswood or 
American linden (Tilia americana), chestnut, cherry, but- 
ternut, walnut, hickory, poplars, magnolias ; and. of the 
Oonifere—the pines, balsams (Abées), tamarac (Larix 
americana), cedars (Thuja occidentalis) and (Juniperus 
virginiana), hemlock spruce (4 bies canadensis). 
The most important of these great mixed forests are in 
Canada, extending from the northern shores of Lake Erie, 
in lat. 42°, to the northern limits of Canada. Some of 
these trees have a very extensive range north and south. 
The sugar maple (Acer saccharinum), is found near Lake 
Winnipeg, in lat. 50°, and the black sugar maple (A. ni- 
grum), in lat. 82°, in Louisiana. The beech and elms have 
a range quite similar to the maple. The American linden 
also goes as far northward. The white pine (Pinus Strobus), 
prevails in the northern parts of these forests, and the red 
pine (P. resinosa), in the southern. The red cedar (Junt- 
perus virgimana), has the greatest range, extending from — 
lat. 26° in Florida to 67° within the arctic circle. The 
wild cherry, too (Prunus americana), a large forest tree, and 
the shad-bush (Amelanchier canadensis), extend over nearly — 
as many degrees. The trembling poplar (Populus tremu- 
