30 EXPLORATIONS FROM A. D. 1800 To 4. D. 1832. 
passing from the sources of the Missouri to the Pacific Ocean. An expedition to this effect was 
actually fitted out by the aid of Mr. Whitworth, when the growing troubles of the colonies 
with the mother country led to its abandonment. 
Mr. Schoolcraft says, in his introductory observations on the sources of the Mississippi, that 
‘American geography may be said to have had three important problems to solve in modern 
times. The first and second of these related to the source of the Missouri and the course and 
termination of the Columbia. Both were substantially resolved by the expedition of Lewis 
and Clarke, under the administration of Jefferson," &c. ‘‘The true source of the Mississippi, 
which forms the third topic of inquiry, was brought into discussion at the same period." 
Messrs. Allen and Schooleraft resolved this third important problem, so that it might seem, 
according to Mr. Schoolcraft, that American geography had no more problems to solve. Lewis 
and Clarke did probably determine the source of the Missouri, although it is yet a question if 
the Yellowstone river, with its affluent, the Bighorn; may not be a still more distant source. 
The character of the Missouri below the mouth of the Yellowstone is, however, so similar to 
that above, and so different from the Yellowstone itself, that the name of the main river was 
properly given to the branch which now bears it. Of the Columbia, however, Lewis and 
Clarke determined but little, and that only below the junction of Lewis Fork. Its source, 
even to this day, is undetermined by any accurate exploration. But if these were the great 
problems of modern American geography, surely there were more than three. The sources of 
the Rio Grande del Norte, of the Yellowstone, of the Great Colorado of the West, might have 
been considered of equal importance, and the discovery since of large lakes of salt water, of 
large basins and long rivers with no outlets to the ocean, show that the field was not yet 
deprived of objects of great geographical interest. 
A. PER MAP OF NORTH AMERICA: PHILADELPHIA, 1826. 
Igive lesen a reduced copy of a portion of this map (Plate IIT) which purports to include 
‘tall the recent geographical discoveries" up to that date. On this we see Rio los Mongos and 
Rio Timpanogos flowing from Lake Timpanogos to the Pacifie, from near the true position of 
Great Salt Lake, and the Rio Buenaventura flowing from Lake Salado to the Pacific. At what 
time and for what reason these rivers gained a place on the maps of that period I am not 
acquainted. The Multonomah (Willamette) is still represented as heading to the east of the 
Cascade range. This map shows that no advancement had been made in accurate knowledge 
of the regions west of the Rocky mountains since the exploration of Lewis and Clarke. 
