
CAPABILITIES WITH REFERENCE TO SETTLEMENT. 311 
suitable to the invaders, and especially unsuited for their propagation 
and increase. 
731. The supply of wood for building, fencing, and fuel, over a great 
part of the North-west, is a matter which appears to require immediate 
attention. The existence of great areas of plain, almost entirely desti- 
tute of timber trees, is now generally known, and on another page of 
this Report, it has been attempted to estimate the part of this region 
which lies to the north of the Boundary-line. Apart from the great imme- 
diate disadvantages of so vast an extent of treeless prairie, its presence, 
and the complete absence of forest-clad areas, cannot but have a 
very serious effect on the climate of the whole interior region of the 
continent. 
732. Several writers have devoted attention to the cause of the tree- 
lessness of the plains; and while on one hand it has been argued that 
the whole, or almost the whole, interior region of the continent has been 
forest clad; it has been contended by others that the greater part of the 
area has never been covered with trees, and certain reasons have been 
brought forward which show, in the opinion of those on this side of the 
controversy, that the prairies are incapable of supporting a forest growth. 
The plains are known to have been thickly clad with coniferous and other 
forests, in the Tertiary period, but there are other circumstances tending to 
show that in comparatively modern, and post-glacial times,a very much 
greater area was tree-clad than at present. Chief among these is the great 
abundance of land and fresh-water shells, in the later deposits of the 
Missouri, already mentioned, and the gradual desiccation, which, on 
the testimony of many observers, has been, and is still, going on over 
great areas of the West. This, though it may at present be intensified 
by extra-terrestrial influences, bringing about cyclical changes of cli- 
mate, cannot be entirely attributed to such causes, but is the natural 
result of the decreasing area of the region of forest. Against these 
facts may be placed others tending to an opposite conclusion, or at 
least to the modification of the idea of the former universality of 
forests. The absence of systems of drainage vallies in many regions, 
has been already referred to, as showing the improbability of former 
great rainfall. The absence of any remains of old forests, or of roots, 
or drift-wood in the subsoil and alluvial deposits of the greater part 
of the plains, would appear to have a like meaning. It would seem 
most accordant with the facts, as they are at present known, to con- 
clude that, since the glacial period, the plains have never been entirely 
