22 
BOTANY OF THE ROUTE. 
ten to forty feet high, and generally parallel to the mountains. At short intervals occur lakes, 
small but beautifully clear, though usually without visible outlet, the gravelly soil rapidly 
absorbing the water during the dry season. Few, however, dry up completely, and they 
become neither muddy nor stagnant, thus indicating, perhaps, a subterranean flow. Around 
these are beautiful groves of poplar, aspen, ash, maple, and a few pines and oaks. Scattered 
over the surface are rounded hills, looking like islands in the level plain, and covered with 
groves of the usual fir, which also sometimes grows on the slopes of the terraces. The whole 
plain looks like a magnificent park ornamented by the highest skill of the landscape gardener, 
while to the southeast-, and in full view from all parts of it, stands the majestic Mount Rainier, 
forty miles distant, though in appearance not more than five. 
On the much discussed subject of the mounds so abundant on the praries about Puget 
Sound, I must make a few remarks, since Mr. Gibbs has suggested that they might have been 
produced by the immense growth of the “giant root,” (Megarhiza Oregana ,.) forming a nucleus 
around which the soil has been gradually washed away.—(Yol. I, p. 469.) I have noticed this 
plant quite as often on level ground and in hollows as on these mounds, and have found deep 
cavities where its roots have decayed. I cannot, therefore, consider it a cause any more than 
roots and stumps of other kinds, which never produce mounds so symmetrical and uniform as 
these are found. I would suggest that they may have been produced by eddies and whirlpools, 
probably at a time when this sound formed the estuary of a great river like the Columbia, or 
perhaps these prairies were branches of the great system of northwest sounds, which extends 
from the Columbia river to Sitka, or further. I have seen such whirlpools in the narrow inlets 
of the sound, during the violent ebb of the tide, that seemed to me quite capable of thus 
raising mounds of gravel, just as is done by the eddies of the wind with the light sand along 
the sea shore and on the plains. Any vegetable origin must be quite inadequate to produce 
such mounds as I have seen along Black river, which I believe were never seen by Mr. Gibbs. 
There they stand so close together that it is impossible to walk between them without stepping 
on the adjoining slopes, and, while standing at their bases, I could not see over them. Such 
covered the surface for miles near the western border of the prairies, there being r one in the 
adjoining forest. Their form, as is there most distinctly marked, is very perfectly circular ; 
height from a scarcely perceptible swell to eight feet, and diameter at least six or eight feet. 
Their bases do not coalesce, though close together when they are well marked. The low ones 
seem to have been partially covered, so as to conceal their bases, and form level intervals 
between the summits that still protrude. 
Note. —Mr. Gibbs, in his Geological Report, dated two months later than the above reference, 
(Yol. I, p. 486,) says that their origin “is clearly due to water.” 
In a journey up the Chehalis and down the sounds to the Straits of Fuca, in March, 1855, I 
found vegetation as far advanced as is usual in May at New York. Strawberries,'&c., were 
beginning to flower, and many summer birds had arrived, including the delicate humming bird, 
swallows, and warblers. Indeed, the mildness of the winters makes the prairies more green 
and beautiful at that season than in summer, and up to the end of December, 1853, I found 
several flowers still blooming about Yancouver. 
Many of the richest prairies are much injured by a- dense growth of fern or brake, which 
grows on them eight feet high, and as it also occurs about two feet high on the poorer soils, 
becomes a sure indication of richness. It is said that by cutting off for a few times at a height 
of several inches the stems will “bleed” to death, the sap running so as to exhaust the roots. 
