FIELD PARTIES AND OPERATIONS, 79 
camps, some hundred and seventy miles south of Fort Benton, by Lieutenant Mullan, and the 
Blackfeet, the same distance north, by Mr. Stanley; and that the exploring parties, Lieutenant 
Mullan, by the Hell Gate, Lieutenant Donelson, with the engineer parties, by the Blackfoot trail, 
all rendezvoused at the St. Mary’s village by the 30th September, except Mr. Tinkham, who 
reached the St. Mary’s valley on the 6th of October. Mr. Lander, who had gone sixty-five miles 
on his way to examine the Marias Pass, on the arrival of Lieutenant Saxton, made, under the 
direction of Lieutenant Donelson, a reconnaissance of the Marias, Teton, Sun and Dearborn 
rivers, and crossed the dividing ridge of the Rocky mountains by the pass of Lewis and Clark 
on their return route some eight miles northwest of Cadotte’s Pass, crossed by the main party, and 
came upon the common trail thirteen and a half miles lower down the pass; and Mr. Tinkham, 
before reaching the narrow defile ending in Hell Gate, examined a route from the pass to the 
Jocko river flowing into Clark’s fork, and then came into the St. Mary’s valley in Lieutenant 
Saxton’s trail. 
At St. Mary’s valley I found Lieutenant Arnold in charge of that post with six men and a 
considerable depot of provisions. Lieutenant Saxton’s route to that post was by the Dalles, 
Wallah-Wallah, Peluse, Coeur d’Alene prairie, Clark’s fork, and Jocko river. He reached the 
village on the 28th of August, and started for Fort Benton with a party of eigliteen men on the 2d 
of September. Lieutenant Macfeely, in command of twenty-six enlisted men and quartermaster 
employés, lefi that village on the 4th day of September, by the southern Nez Perces trail, for 
the Dalles. 
Lieutenant Mullan was placed in charge, with fifteen men, of a meteorological post at the St. 
Mary’s village, with orders to explore a route to Fort Hall, and to make all possible examinations 
of the mountain passes, especially as to the depth and continuance of snows; and Lieutenant 
Donelson was sent over the general route explored by Lieutenant Saxton, with directions to send 
Mr. Lander down the St. Mary’s river, and meet him at Horse Plain. Mr. Tinkham was sent 
back over the Rocky mountains by the Marias Pass, with orders to return, by some southera 
pass, to the St. Mary’s village, thence by the southern Nez Perces trail to Wallah-Wallah, and 
thence over the military road to Steilacoom and Olympia. Dr. Suckley was directed to go down 
the St. Mary’s river, Clark’s fork, and the Columbia, and to make the best exploration his means 
permitted. 
Leaving the St. Mary’s valley, opposite Hell Gate, on the 7th of October, I pushed with a small 
party over the Coeur d’Alene mountains, and resting my animals one day at the Coeur d’Alene 
mission, I pushed on to Colville, and reached that place on the 18th of October, the day of the 
crossing of the Columbia river at that point by Captain McClellan. 
To guard against the possibility of Captain McClellan’s passing the eastern division, on his 
way to the Rocky mountains, Lieutenant Donelson was directed to despatch Lieutenant Arnold 
on his second crossing of Clark’s fork, by the northern trail to Colville, and orders were left at 
Colville, directing him to go up the Columbia river, make a general reconnaissance of the river 
in the vicinity of the 49th parallel, and then repair to Wallah-Wallah by the route of the left bank 
of the Columbia, by the Grand Coulée, and by the mouth of Snake river. 
Word was sent to Lieutenant Donelson to meet the western division at a camp south of the Spo- 
kane river, and arrangements were made to complete the exploration of the Snoqualme Pass by a 
small party with one of the assistant engineers, Mr. Lander, and carry the line down to the harbor 
on the sound; to explore the route crossing the Columbia above the mouth of Snake river, and lead- 
ing by its north bank to Vancouver, both parties under the charge of Captain McClellan, who was 
also to determine, in his way, one or two doubtful points as to the geography of the country; to 
explore a third route, by Lieutenant Donelson, from the Coeur d’Alene mission to Wallah-Wallah, 
and thence down the south bank of the Columbia river to the Dalles, and to send the animals and 
men not needed for those duties along the usual trail to Wallah-Wallah, under Lieutenant Hodges. 
On a careful inspection of the animals, made by Captain McClellan and Lieutenant Donelson, 
