TOPOGRAPHY OF ROUTE FROM THE MISSISSIPPI TO THE COLUMBIA. 169 



ration, 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 Mullan, of his 

 exploration of Kootenaies river, exhibiting a highly diversified country, with the usual character 

 istics of the whole mountain section.) 



The spurs of the Bitter Root and Cceur 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 explorations 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 of the whole western district. Lieut. 

 Mullan was the most fortunate, having found, he believes, a practicable railroad and wagon route 

 through the Cceur 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- 

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