TOPOGRAPHICAL REPORT ON WESTERN DIVISION. 21 
streams, enter these lakes. They are very deep, but no exact soundings were taken for want of 
a line of sufficient length. There is a large lake on the Samahma river, eight miles above its 
junction with the Columbia. This lake, Kleallum, is seven miles long, and from one to three 
miles broad. The Samahma at its head is a bold mountain stream in character, and is about 
fifty feet wide one mile above the head of the lake. All of these lakes are embosomed in and 
entirely surrounded by mountains, heavily timbered with fir, pine, and cedar. The mountains 
around Pilwaltas particularly are very sharp and rugged granitic peaks, some of which are round 
and bald, and others needle-shape in structure. The Samahma river below the lake is sixty feet 
wide and very crooked and rapid. The Yannoinse and Schwock are streams thirty feet wide, 
with rapid currents and rocky bottoms. The Yakima is from eighty to one hundred feet wide, 
and the ford at Ketetas is shallow and good. It is usually from three to five feet deep, and 
fording impracticable at high water. After leaving Ketetas plain, the Yakima bends to the south 
until it receives the waters of the Atahnam, and then turns again to the east, and runs generally 
in that direction to its junction with the Columbia, about twenty miles above Wallah-Wallah. 
Mr. George Gibbs, who followed this river to its mouth, reports that the valley is continuous below 
the Atahnam, and from six to ten miles wide to within a short distance of the Columbia, where it 
is cut off by a range of low hills running nearly parallel to the latter. It is uniformly barren, 
except a few small spots along the margin, which are overflown by the freshets. The basalt 
continues to the Columbia. Bunch-grass grows only upon the hills, the low sandy plateau being 
covered with wild sage. Cotton-wood grows upon the banks as far down as the mouth of the 
Pisca, below which there are only a few willow bushes. The country on the Columbia at the 
mouth of the Yakima is a sandy desert covered with sage. The banks of the Columbia have a 
uniform height of about thirty feet above the river. All the country north of the Yakima, between 
that and the Columbia, must be more or less mountainous or high and broken table-land, as the 
spurs between the branches of the Yakima, coming out from the main range, unite to the east of 
that river along its southern bend, and run off together in a rough broken chain towards the 
Columbia. Leaving Ketetas on the Yakima, the trail bears to the east of north for sixteen miles 
to the top of the divide, and thence eighteen and a half miles to the west of north to the mouth of 
the Wenatsapam river. For eight miles the trail lies across Ketetas plain to the gorge from 
which the Nahnum comes from he mountains, and crosses the Nahnum at this point. This 
river is rapid and stony, and about thirty feet wide. There is a fall of three feet upon it two miles 
below the ford. Here we commence the ascent of the divide between the Yakima and the 
Columbia. The Nahnum runs for several miles from the gorge along the left of the trail in a 
very deep cafion, and then leaves it, bearing to the northwest. To the top of the divide 
the ascent is gradual except in places, and the country is rough and basaltic, with a great deal of 
loose broken lava upon the surface. This spur is timbered, but the trees do not extend to the 
east beyond one or two miles from the crossing, and then only in strips and points; timber, 
pine, and open for the most part. Just before reaching the divide, the trail crosses two small 
rivulets, the heads of the streams running through Ketetas plain to the east of the Nahnum. 
The top of the range, which is higher than the other spurs, is comparatively level for several 
miles, and has small ponds and swampy places on it. Owing to this flat, level character, the 
trees upon it are not seen from either the Yakima or Columbia, the range presenting a bare, 
barren, desolate look. From the summit a sharp angular range of snow mountains is seen off 
to the left of the trail, and commencing between the summit and the Columbia, run off towards 
the northwest. Mount Stuart is the most prominent, and is nearest the Columbia. The 
Samahma, Yannoinse, Schwock and Nabnum branches of the Yakima, and the Skilkantin, a 
branch of the Columbia, and several branches of the Wenatsapam river, head in these snow 
mountains. The descent from the spurs is by plateaux—that of the first four being abrupt and 
rocky. The pine timber ceases about four miles before reaching the Columbia. The Skilkantin, 
a stream twenty feet wide, rapid and stony, is crossed two miles above its mouth, and the trail 
