second and forty-fourth degrees, near the sources of the Rio Colorado, [Green River] the Platte, the Yellowstone, and the Missouri rivers. Its western course till it reaches the Blue Mountains, and hence its northern direction till it joins the Columbia, together with its principal tributaries, are sufficiently known to you and have been amply described already.
We found about a dozen Indian lodges called the Palooses, a portion of the Sapetan or Nez Perces tribe. We procured from the Indians here some fresh salmon, for which we made them ample return in powder and lead. But as the grass was withered and scanty, and the pilfering disposition of these Indians rather doubtful, we resolved on proceeding eight or ten miles farther, and encamped late
in the evening on the Pavilion river. The Nez Perces and Spokan plain is at least a thousand feet elevated above the bed of the river. It is dry, stony, undulating, covered with bunch and nutritious grass, with prickly pear and wormwood. The basaltic and volcanic formations which extend through the whole of this region are really wonderful. We frequently passed ponds and small lakes embedded between walls of basaltic rocks - immense ranges of dark shining pentagonal pillars, as if forced from the bosom of the plain, extend for some miles, resembling not unfrequently forts
and ancient ruined cities and castles. We encamped several times near small but beautiful lakes, where ducks and geese, with their young broods, were swimming in great numbers. The Indians frequent these regions in search of the bitter and camas roots, very abundant here. In every one of their old encampments we observed great quantities of prairieturtle shells, a proof of their being numerous and serving as
food for the savages. Pheasants or quails were very abundant - we daily killed what we wanted for our meals.
On the fifth day of our departure from Walla Walla, we reached the Spokan river, and found a good fording for our animals. You will see with pleasure the chart I have made of the headwaters of this river, which, though beauti36