12 ROUTE NEAR THE FORTY-FIRST AND FORTY-SECOND PARALLELS. 



The work upon this route, under Governor Stevens, embraced a wider field of exploration 

 than that upon any other explored, and a great amount of topographical and general inform 

 ation was collected in relation to the country traversed . The necessary astronomical observa 

 tions were not made to determine accurately the longitudes of the several stations, and the loss 

 of his barometrical observations, after the completion of the field-work, left no means of revising 

 and verifying the profile of the route. 



The examination of the approaches and passes of the Cascade mountains, made by Captain 

 MeClellan, of the Corps of Engineers, presents a reconnaissance of great value, and though 

 performed under adverse circumstances, exhibits all the information necessary to determine 

 the practicability of this portion of the route, and reflects the highest credit on the capacity 

 and resources of that officer. 



ROUTE NEAR THE FORTY-FIRST AND FORTY-SECOND PARALLELS OF NORTH LATITUDE. 



About one-half of the route in this latitude, extending from the Missouri river to Fort 

 Bridger, on a tributary of Green river, has not been explored with a special reference to the 

 practicability of constructing a railroad, and the reports do not contain all the details neces 

 sary to the elucidation of the subject. The information respecting it is to be found in the 

 reports of Col. Fremont and Capt. Stansbury. 



From Fort Bridger to Fort Reading, on the Sacramento river, the exploration has been 

 made by Lieut. E. G. Beck with, under the appropriation for that purpose. 



The route may commence on the Missouri, either at Fort Leavenworth, about 245 miles 

 from the Mississippi at St. Louis, or at Council Bluffs, about 267 miles from the Mississippi at 

 Rock Island, ascend the Platte and enter the eastern chain of the Rocky mountains (the Black 

 Hills) by the Xorth fork and its tributary, the Sweet Water. Another route, by the South fork 

 and a tributary called Lodge Pole creek, has been suggested by Capt. Stansbury as shorter and 

 less expensive ; but the information respecting it is not sufficiently full to make further 

 mention of it necessary. 



From the Missouri river to the entrance of the Black Hills, 30 miles above Fort Laramie, 

 520 miles from Council Bluffy, and 755 miles from Fort Leavenworth, the route resembles 

 others from the Mississippi to the Rocky mountains, and needs no special mention. Its cost 

 per mile will be about the same. 



The route west of this point crosses many lateral streams that have cut deep ravines into 

 the soil, and leaves the Platte just below the Hot Spring Gap, above which it is walled in by 

 canons. To avoid these, the route crosses a range of hills 800 feet above the river, and descend 

 ing to the Sweet Water, a branch of the Platte, follows that stream to its source, where the 

 summit of the plateau of the South Pass (elevation 7,490 feet) is attained. The valley of the 

 Sweet Water is generally rather open, but occasionally it cuts through mountain spurs, forming 

 canons. 



From the first gorge in the Black Hills to the summit of the pass, 291 miles, the wotfv will 

 be difficult and expensive, and is assimilated in amount to that of the Baltimore and Ohio 

 railroad. 



From the South Pass the route follows down Sandy creek, a tributary of Green river, to 

 the crossing of the latter, and thence to Fort Bridger, (elevation 7,254 feet,) on Black s fork, 

 likewise a tributary of Green river. The amount of work on this section would be consid 

 erably less than on the preceding. 



From Council Bluffs to Fort Bridger the distance is 942 miles; from Fort Leavenworth 

 1,072 miles. 



The route now ascends the divide between the waters of Green river and those of the Great 

 Salt lake, by the valley of Black s fork, or of one of its tributaries, with grades of 69.5 and 

 40.3 feet per mile. The summit is a broad terrace at the foot of the Uinta mountains, and 

 has an elevation of 8,373 feet. From this point the line descends over the undulating country 



