EXPLORATIONS FROM A. D. 1832 To A. D. 1844. 33 
Captain Bonneville's maps, which accompany the edition of Irving's work, published by 
Carey, Lea & Blanchard, in 1837, (the later editions generally do not give the original maps,) 
are the first to correctly represent the hydrography of this region west of the Rocky mountains. 
Although the geographical positions are not accurate, yet the existence of the great interior 
basins, without outlets to the ocean, of Great Salt lake, of Mary's or Ogden's river, (named 
afterwards Humboldt by Captain Frémont,) of the Mud lakes, and of Sevier river and lake, 
was determined by Captain Bonneville's maps, and they proved the non-existence of the Rio Buena- 
ventura and of other hypothetical rivers. "They reduced the Wallamuth or Multonomah (Willa- 
mette) river to its proper length, and fixed approximately its source, and determined the 
general extent and direction of the Sacramento and San Joaquin rivers. The map of the 
sources of the Yellowstone is still the best original one of that region. 
As there is no name on the published map to show by whom it was constructed, I wrote to 
Colonel Bonneville in relation thereto, enclosing him a copy of the map. I make the following 
extracts from his reply: - 
“Ga River, N. M., August 24, 1857. 
** DEAR SIR: I thank you for your desire to do me justice as regards my map and explorations 
in the Rocky mountains. I started for the mountains in 1832. * * * * J left the 
mountains in July, 1836. and reached Fort Leavenworth, Missouri, the 6th of August following. 
During all this time I kept good account of the course and distances, with occasional observa- 
tions with my quadrant and Dolland's reflecting telescope. * * * * * I plotted my 
work, found it proved, and made it into three parts: one a map of the waters running east to 
the Missouri State line; a second of the mountain region itself; and a third, which appears to 
be the one you have sent me, of the waters running west. On the map you send I recognize 
my names of rivers, of Indian tribes, observations, Mary's or Maria's river, running southwest, 
ending in a long chain of flat lakes, never before on any map, and the record of the battle 
between my party and the Indians, when twenty-five were killed. This party clambered over 
the California range, were lost in it for twenty days, and entered the open locality to the west, 
not far from Monterey, where they wintered. In the spring they went south from Monterey, 
and turned the southern point of the California range to enter the Great Western Basin. 
all the maps of those days the Great Salt lake had two great outlets to the Pacific Ocean: one of 
these was the Buenaventura river, which was supposed to head there; the name of the other 
I do not recollect. Tt was from my explorations and those of my party alone that it was ascer- 
tained that this lake had no outlet; that the California range basined all the waters of its eastern 
slope without further outlet; that the Buenaventura and all other California streams drained 
only the western slope. It was for this reason that Mr. W. Irving named the salt lake after 
me, and he believed I was fairly entitled to it. The Great Lava plain was never known as 
such; until my report drew attention to its character, it was even confidently asserted that 
there was no prismatic basalt columns in that region. I saw it perfectly formed once only, and 
this on Snake river, below Gun creek. The Three Buttes have often been my camping ground. 
I wintered once on Salmon river, by my observation 45° 50’ 24” north latitude. It was from 
my observations and plotting that the headwaters of Snake river, of the Columbia, Muscle 
Shell, and Yellowstone; headwaters of the Missouri and Sweetwater, of the Platte, and those 
of the Colorado of the West, were brought together in one view, as reported in my journal; 
