GEOGRAPHICAL MEMOIR. 251 
around the Cascades of one mile and a half. The next obstruction is at the Dalles, two hundred 
and five miles from its mouth. At this place the Columbia makes a bend like a horseshoe 
towards the south and runs through a basaltic trough, with walls about twenty feet in height 
and two hundred yards apart; the current is very rapid, but is not rough. For canoes, a 
portage of eight hundred paces avoids this obstruction; for steamers, canaling a considerable 
longer distance would be required. In the absence of careful surveys, I have not the means 
of stating the distance along which improvements must be made to furnish continuous navi- 
gation, or, in the absence of such improvements, the shortest land portage which would be 
required. Р 
Тһе portage now in use is from the Dalles to the mouth of the Des Chutes, a distance of eleven 
miles. But this distance can unquestionably be very much reduced. For the past two seasons 
the army supplies for the Walla-Walla post have been transported in sailing vessels from the 
mouth of the Des Chutes river to Old Fort Walla-Walla, and it is known that from that point to 
Priest’s Rapids no obstructions exist. At Priest’s Rapids canaling would probably be required, 
or a land portage of some three miles. The other obstructions are: Buckland’s Rapids, sixty 
miles above Priest’s Rapids; Ross’ Rapids, near the mouth of the Methow river; and Kettle 
Falls Ross’ Rapids would not be an obstruction to steamers, but both at Buckland’s Rapids 
and at Kettle Falls locks and canals would probably be required, more especially at the Kettle 
Falls, where the Columbia pitches over a ledge of rocks, making a perpendicular fall of about 
fifteen feet. “Іп order to make the Columbia river continuously navigable from its mouth to 
Kettle Falls, a distance of 135 miles, locks and canals will be required at the Cascades and the 
Dalles, and probably at Priest’s Rapids, and at Buckland’s Rapids, giving the following reaches 
of navigable waters: 
Miles. 
Entrance: to Cascadóss -. uel 1 EL OSO Cr A» Ee QU) e а Se REE NON 165 
Cascades to Dalles... +--+ cere cere cers wa dee 28 Ri. ырма ос” А ааа ыз 40 
Dalles to Priest's Rapids... errs s+" Be aE eh qud dev ene V сті 179 
Priest’s Rapids to Buckland’s Барібв.......:.-..- ress rte tttm 66 
Buckland’s Rapids to Kettle Falls- <- tttm 974 
‘Above Kettle Falls there is a navigable reach of some fifty miles, to a fall in the Columbia, a 
little north of the 49th parallel. It will be well to state that at high water steamers could 
probably ascend the whole distance from the Dalles to Kettle Falls, say from the middle of May 
to the middle of J uly. Steamers have been running regularly on the two first-mentioned reaches 
for some years, and a steamer is now ready to run on the third reach, between the Dalles and 
Priest’ в Rapids. The business has increased quite rapidly; so much во, that for three years 
there have been from Portland and Vancouver two lines of steamers to the Dalles, and the rates 
of freights and passengers haye become greatly reduced. Тһе annual freshet of the Columbia 
is caused by the melting of the snow in the Alpine regions of the Rocky, Bitter Root, and 
Cascade mountains, and, as a consequence, takes place in the warm months of spring and early | 
summer, commencing about the middle of April, and attaining its greatest height usually, and 
very regularly, by the 15th of June, at which time all the rapids from the Dalles to the Kettle 
. Falls, near Colville, are, so to speak, submerged. Its great southern tributary, Snake river, 
has a general course in a semi-circle from its sources, in latitude 44?, longitude 112?; running 
first south, and in latitude 42° 30, curving around to the west, northwest, and finally north, to 
