Sioux City Academy of Science and Letters. 57 
THE SMOKING BLUFFS OF THE MISSOURI 
RIVER REGION. 
By H. C. POWERS. 
When the Lewis and Clark expedition came up the 
Missouri River in 1804 on its way to the Pacific coast, 
the Indians, who lived along the river in Northwest 
Iowa and farther up, told them of smoking bluffs which 
seemed to be on fire deep down from the surface. They 
regarded them as the home of spirits and feared to go 
upon or near them. These bluffs were seen by many of 
the early white discoverers who passed up the river. 
On pages 83-4 of the report of that expedition, by 
Elliott Coues, is found the following account from the 
Journals of Lewis and Clark concerning a visit to one of 
these bluffs: “Aug. 24th we proceeded two and a quar- 
ter miles to the commencement of a bluff of blue clay 
about 180 or 190 feet high, on the south side; it seems to 
have lately been on fire, and even now the ground is so 
warm that we can not keep our hands in it at any depth; 
there are strong appearances of coal, and also great 
quantities of cobalt, or a crystallized substance resem- 
bling it.” The following note by the editor is also found 
on page 84 of the same report: “The formation of these 
bluffs, and the attendant phenomena suggestive of vol- 
canic action, were very early the subject of observation 
and speculation. They were formerly styled pseudo-vol- 
canoes by Nicollet in 1848, who also called attention in 
this connection to the peculiar, light, spongy stone, 
which Lewis and Clark repeatedly speak of as pumice, 
but which he (Nicollet) names pumiferous stone, as not 
being true pumice but resembling it. He found no hills 
smoking when he ascended in 1839, nor did Lewis and 
Clark, but he was credibly informed that such an occur- 
rence had been witnessed in the interior.” 
