TOPOGRAPHY OF ROUTE FROM THE MISSISSIPPI TO THE COLUMBIA. 169 
vation, and altogether it seems but to require the advent of the white man to make it a place of 
considerable importance. The country also around the Flathead lake is reported to be well 
adapted for settlements, having extensive open prairies and numerous streams. From the con- 
fluence of the Bitter Root and Hell Gate rivers to that of the Bitter Root and Flathead rivers, the 
valley is of a rugged and difficult character. The mountains close upon the river, forming an 
intricate and formidable canon for some ten or twelve miles above the junction, the course of the 
river being extremely sinuous. The formation of the country, however, affords the chances of 
more than one favorable detour. With reference to this section of the main river, a glance at 
the map will save the necessity of detailed description here, and which, no doubt, will be found 
in the reports of the engineers. Thence the valley of Clark’s fork is densely timbered along to 
Pend d’Oreille lake, with the exception of a few prairie spots; with but little level intervale, the 
mountains sloping steeply towards the river, and abounding in wild, romantic scenery, especially 
where the river widens considerably, embracing numerous islands, with their growth of cotton- 
wood. For the sake of the geography alone, it is to be regretted that none of the exploring par- 
ties visited the country directly north of Clark’s fork and Pend d’Oreille lake. The Hudson’s Bay 
people report a large and beautiful sheet of water called by them Lake Rootham, and surrounded 
by a wild belt of excellent country. (See a subsequent report from Lieutenant Mallan, of his 
exploration of Kootenaies river, exhibiting a highly diversified country, with the usual character- 
istics of the whole mountzin section.) 
The spurs of the Bitter Root and Coeur d’Alene mountains, depending from the southwest side 
of the great mountain feature, are but little known: only one party went through from the head 
of the St. Mary’s or Bitter Root valley to the western plains; but this line of reconnaissance was 
so far from the general operations, that a considerable region on that side remains to be explored. 
(The subsequent ex plorations of this region leave but little to be said. The accounts of Lieut. 
Mullan, Mr. Tinkham, and Lieut. Macfeely, with the older explorations of Lewis and Clark, con- 
cur in proclaiming the wild and inhospitable character ofthe whole western district. Lieut. 
Mullan was the most fortunate, having found, he believes, a practicable railroad and wagon route 
through the Coeur d’Alene mountains.—See the several reports.) 
One of the most singular results of the survey of the dividing ridge by the numerous passes is, 
that the barometer, wherever used, shows a marked difference of elevation between the slopes 
on either side, amounting to as much as five or six hundred feet, that being the difference of the 
observations taken at the heads of the streams rising on both sides at the very base of the ridge. 
Partial information led to the belief that these differences were all one way, so that the general 
base on which the mountains rest was supposed to have just so much greater elevation than any 
corresponding part of the eastern slope; but this has not proved to be the case: in Cadotte’s or 
the Blackfoot Pass, the western is the higher side; in Clark’s Pass, the eastern ; the eastern also 
in Marias Pass; varying in the same way, it may be supposed, in the other passes where alti- 
tudes were not obtained. ‘ 
From the data of such a rapid survey it is not possible, nor will it be considered necessary, 
to ascertain the precise arrangement of the smaller branches of the mountains on that principle 
of order which is known to obtain, even in the fantastic outlines of mountains and rivers. The 
extensive explorations of Mr. Tinkham, civil engineer, and Lieutenant Mullan, United States 
army, from the basis of the odometer survey, have developed the leading features with reliable 
accuracy, as they have been feebly indicated in this report. In accordance with the general 
view here attempted, it will perhaps be sufficient to observe that, although the whole region is 
generally pretty closely packed with mountains, still the available country in the valleys and 
prairies can be reckoned—it is not too much to say—by thousands of square miles, requiring 
only roads—the leading-strings of nursing nations—to develop its capabilities ; and if the success- 
ful cultivation of mountain slopes and unpromising soils in densely peopled countries be con- 
22 f 
