Yellowstone-Missouri confluence — Patrick Gass: April 26, 1805

proceeded 10 miles came at 12 o’clock to the mouth of the
LEWIS AND CLARK EXPEDITION 79
Jaune and halted: Captain Lewis and his party had not ar-
rived. I went up the point about 9 miles, where there are the
most beautiful rich plains, I ever beheld. I saw a large pond
or lake. — Captain Clarke while I was absent measured both
rivers: and found the breadth of the Missouri to be 337 yards
of water, and 190 of a sand beach; total 527 yards. That of
the Yellow Stone river 297 yards of water and 561 of sand;
total 858 yards. The mouth of this river is 1888 miles from
the mouth of the Missouri; 278 from fort Mandan and 186
from the mouth of Little Missouri.
The river Jaune is shallow, and Missouri deep and rapid.
In the evening Captain Lewis with his party joined us; and
had brought with them a buffaloe calf, which followed them 7
or 8 miles. We killed a number of calves, and found they
made very good veal. There are a great many signs of beaver
in this part of the country. We encamped on the point all
night.