CHAPTER VI. 
INCIDENTAL OBSERVATIONS ON THE MISSOURI RIVER, AND ON THE 
MAUVAISES TERRES (BAD LANDS). 
In the instructions forwarded to me in the spring of 1849, by the Commissioner 
of the General Land Office, for my guidance during that season, I was directed to 
extend the Survey into Iowa more than had hitherto been done. In fulfilling these 
instructions, I was desirous, if possible, to connect the geology of the Mississippi 
Valley, through Iowa, with the cretaceous and tertiary formations of the Upper 
Missouri; a matter very important to the proper understanding of the formations of 
the intervening country, which it had been made my particular duty to explore. 
I visited St. Louis early in May of that year, for the purpose of making the 
necessary arrangements to ascend the Missouri, with the intention of going up the 
Sioux River, crossing from its head-waters by land, near the northern boundary 
line of Iowa, and descending the Des Moines in canoes, if it was found practicable 
to make a portage to the head-waters of that stream. 
But, owing to the difficulty of obtaining men, in consequence of the panic caused 
by the prevalence of the cholera on the Missouri, I was compelled to abandon my 
first intention ; and finally determined to commence my explorations on the Iowa 
and Des Moines Rivers and adjacent country ; intending, towards the close of the 
season, to cross, by land, from the latter river to the Missouri. 
Finding that it would be quite unsafe to rely on procuring supplies so high up 
the Missouri as, on my return route, I intended to strike, I directed Mr. J. Evans, 
one of my subagents, to proceed up that river, for the purpose of making the neces- 
sary deposits of provisions, at suitable points, to meet the wants of my corps. And, 
as it would be impossible for him to rejoin me after performing these duties, I 
further instructed that gentleman, while awaiting my arrival, to employ his time in 
examinations in the vicinity of the Upper Missouri River, as far asthe means at his 
command would admit; and, if possible, to trace out the boundaries of the creta- 
ceous and tertiary formations west of that river, with special reference to their con- 
nexion with the formations of Iowa. 
In following up these instructions, he was enabled to extend his observations 
over a much larger tract than was at first anticipated, in consequence of facilities 
