210 TOPOGRAPHICAL REPORT ON WESTERN DIVISION. 
with grass, and with less rock and lava upon it than on the other spurs crossed. The valley of 
the Wenass is a mile wide. Like the valleys of all the Yakima’s branches, it widens towards 
its Junction with that river, and narrows towards the mountains, the intermediate spurs between 
streams closing upon the valleys towards the main mountains, reducing them virtually to nothing. 
The Wenass is twenty feet wide, eighteen inches deep; bottom strong, current rapid. Wild- 
cherry scrub, aspen, cotton-wood, balm of Gilead, and willow of small growth, are found upon its 
banks. Cactus is found in this valley, and in that of the Nahchess. ‘The country between the 
Wenass and Yakima is a high, barren, broken, basaltic table-land, and is mostly destitute of 
any kind of vegetation. Immense fields of broken lava, sharp and angular, occur upon it. The 
Emptenum, a small stream ten feet wide, runs through it in a deep canon about ten miles from 
Wenass. ‘The descent to and ascent from this stream are made through ravines. In the ravine 
or defile on the northern bank there are some very fine specimens of pentagonal basaltic columns, 
with convex and concave ends. ‘The descent to the Yakima is through a similar defile. This is 
the highest spur crossed since doubling Mount Adams, and is highest between the Wenass and 
Emptenum. The Yakima cuts through this range, in a gorge, about six miles below the point 
at which the trail crosses this river. The Ketetas plain is a high, rolling, basin-shaped plateau, 
lying mostly on the northern side of the Yakima. It is surrounded by high mountains on the 
north and south, the northern chain being about eight miles from the river, and the southern range 
being the one crossed between the Emptenum and the Yakima. These chains unite fifteen miles 
below the ford, and terminate the plain in that direction. Afier uniting, they run to the east, 
towards the Columbia river, ina high range. To the westward the valley extends about six 
miles, and then ceases. The Nahnuin, a bold mountain stream, comes from a gorge in the north- 
ern range nearly north of the ford, and, bending to the east, crosses the Ketetas plain and unites 
with the Yakima near the point where the latter river pierces the southern spur. A second 
stream, a rivulet four feet wide, comes from this same northern range farther to the east, and, 
running through the plain, unites- with the Nahnum near its mouth. ‘There is a stream also 
from the southwest, heading in the southern range, and empties into the Yakima by its several 
mouths just above and below the ford. A small strip of this plain along the river is low, and 
produces good grass; the other portions are either basaltic plateaux, covered with loose lava, or 
they are sandy, barren, sage deserts, cut up with arroyas, and unfit for cultivation. 
The Yakima river has a narrow valley for about ten miles of its course on the southern bank, 
opposite Ketetas plain. Six miles of this narrow valley extend westward from Ketetas to the 
mouth of the Ptehnum, a stream on the right bank from the southwest. Above the mouth of this 
river there is no open valley. A pretty fair trail is found, however, on either bank, by passing 
over low hills and light spurs, for forty miles from Ketetas to the forks, when the Kahchess 
and Yahinse unite to form the main river. The pine timber commences (as you go westward) 
five miles above the Ptehnum, and the country is timbered thence to the forks with open pine 
woods, and no underbrush. Beyond the forks the timber becomes more large and heavy, and 
the underbrush very dense. There are high ranges on both sides of the river, a little back 
from it, up to the forks, beyond which the mountains become very high. 
The principal branches of the Yakima on the right bank above Ketetas, are the Ptehnum 
(already spoken of) and the Wahnoowisha, which come in five miles below the forks. The 
principal northern branches are the Schwock, Yannoinse, and Samahma, their junctions being 
at distances of seventeen, twenty-one, and twenty-six miles respectively above the ford at 
Ketetas. The Yahinse heads in Lake Kitchelus, near the Snoqualme Pass of the main range. 
The Kahchess river is but a short crooked stream, carrying off the waters of two large lakes. 
The first of these, Lake Kahchess, occurs on the river four or five miles above its mouth, and is 
eight miles long, and from one and a half to two miles broad ; one mile above it, and connected 
with it by a shallow, sluggish stream, seventy feet wide, is Lake Pilwaltas. This lake is six 
miles long, and from one-half to one mile broad. Several mountain torrents, but no large 
