SECOND LETTER FROM M. E. BOURGEAU. 15 
and a violet Geranium; a Hedysarum ; the three varieties of Rhi- 
nanthus, &c.,—forming an ensemble most attractive to a botanist. 
At last, on the 7th of August, we arrived at the foot of the 
Rocky Mountains, at the place where stood the ancient fort, in 
lat. 51° 9’ N., long. 115° 4’ W.,—the shores of the River des Arcs 
being 4100 feet above the level of the sea. In ascending this 
river, it is found to flow from a large valley in the interior of the 
mountains, which I have named the Valley des Arcs, as far as the 
second lake, there being a first and a second Lake des Arcs. The 
high peaks of this valley bear the following names: Pic des Pi- 
geons, Pic de la Grotte, Pic du Vent—the last being so named 
from the storms which begin upon its summit. I have explored 
this valley more than any, and especially the mountains on the 
northern side of the Pic du Vent, which I have found peculiarly 
rich in alpine plants. From the river to the limit of the snow, all 
the chain of peaks, as far as the eye can reach, are wooded, prin- 
cipally with three species of conifers, Abies nigra? and alba, and 
Pinus. The latter grows mostly on the southern slopes, and 
does not much exceed thirty feet high—the largest being about 
one mètre in circumference. The Abies nigra? is the largest 
and tallest of the forest-trees which I have observed in the Valley 
des Ares; one which I measured was 3 mètres 23 centimètres 
in circumference. There are also other forest-trees in greater 
or less abundance, as Populus balsamiflua, P. tremuloides, Betula 
papyracea, and B. pumila. The shrubs are mostly the same as in 
the plains, except some Salices of the alpine region. 
There are considerable obstacles to travelling in the mountains. 
The forests suffer almost every year from fires; the trees fall in 
all directions on the ground, and thus form innumerable barricades 
to the progress of horses, and even of men. To ascend to the 
summit of a mountain, a very hard day’s work is needed to cross 
the forest region. This description holds good of all the localities 
which I have visited. 
I am happy to inform you that I have made a good collection 
during this season. I hope that I have gathered the greater 
number of the plants inhabiting that portion of the mountains 
which I have visited, and which I have been able to explore in 
seventeen days. For weighty reasons it was not possible for me 
to remain there longer. 
The month of August is the best period of the year, the plants 
being in perfect flower, and some few in fruit. I observed but 
few withered kinds. 
