Mountains in Miniature: The Loess Hills of Western Iowa

Near Floyd's Bluff, Sioux City, Iowa, circa 1900

The Loess Hills of western Iowa are one of the world’s unique landforms. The hills are unique because of how they came to be.

At the end of the last ice age, the Missouri River attained an impressive width as it flowed through the region of what is today Western Iowa. In modern Monona County, Iowa, the river extended seventeen miles from valley wall to valley wall. The river’s glacial meltwater carried tons of fine particles, or what geologists call “silt.” After the glaciers disappeared, and glacial meltwater no longer entered the stream, the river shrank to a fraction of its former size. Over time, vast expanses of yellowish silt emerged from the river’s depths. Exposed to the drying rays of the sun, the silt became light and powdery. Eventually, the silt went airborne. Once aloft, strong westerly winds carried it eastward before depositing it in dunes on the edge of the valley floor. Gradually, those dunes rose higher and higher until they formed what we now know as the Loess Hills. In the nineteenth century, European-American travelers were deeply impressed with the odd shapes and stark beauty of the hills.  Below are some of their descriptions.

On August 20, 1804, Capt. William Clark penned a description of the loess hill upon which he and his comrades laid to rest Sgt. Charles Floyd. He wrote, “…we Came to make a warm bath for Sergt. Floyd hopeing it would brace him a little, before we could get him in to this bath he expired, with a great deal of composure…we [took] Buried him to the top of a high round hill over looking the river & countrey for a great distance…Situated just below a Small river without a name to which we name & call Floyds river, the Bluffs Sergts. Floyds Bluff…we buried him with all the honors of War…after paying everry respect to the Body of this desceased man…we returned to the Boat & proceeded to the mouth of the little river 30 yd. wide & camped…a butiful evening.”

The artist George Catlin visited Floyd’s Bluff in the 1830s. He wrote the following account of his time in the Loess Hills. “‘Floyd’s Grave’ is a name given to one of the most lovely and imposing mounds or bluffs on the Missouri River…I landed my canoe in front of this grass-covered mound, and all hands being fatigued, we encamped a couple of days at its base. I several times ascended it and sat upon his grave, overgrown with grass and the most delicate wild flowers, where I sat and contemplated the solitude and stillness of this tenanted mound; and beheld from its top, the windings infinite of the Missouri, and its thousand hills and domes of green, vanishing into blue in the distance, when nought but the soft-breathing winds were heard, to break the stillness and quietude of the scene…I could not hunt upon this ground, but I roamed from hill-top to hill-top, and culled wild flowers….”

On April 28, 1811, John Bradbury wrote of the Loess Hills near the mouth of the Platte River. “On gaining the summit of the bluffs, I was amply repaid by the grandeur of the scene that suddenly opened to my view…On looking into the valley of the Missouri from an elevation of about two hundred and fifty feet, the view was magnificent; the bluffs can be seen for more than thirty miles, stretching to the north-eastward in a right line, their summits varied by an infinity of undulations. The flat valley of the river, about six or seven miles in breadth, is partly prairie, but interspersed with clumps of the finest trees, through the intervals of which could be seen the majestic but muddy Missouri. The scene towards the interior of the country was extremely singular: it presents to the view a countless number of little green hills, apparently sixty or eighty feet in perpendicular height, and so steep, that it was with much difficulty I could ascend them; some were so acutely pointed, that two people would have found it difficult to stand on the top at the same time. I wandered among these mountains in miniature until late in the afternoon….”

On April 6, 1850, Thaddeus Culbertson, who had likely read Bradbury’s journal before he traveled up the Missouri, described the Loess Hills near Kanesville, Iowa, which is today’s Council Bluffs, Iowa. “After leaving it [Kanesville], we again entered on the Bluffs and passed over a constant succession of hills. During the whole ride I thought the term “Mountains in Miniature” is the most expressive one to describe these Bluffs. They have all the irregularity in shape…that mountains have, but they have no rocks and rarely timber. Some of the views afforded by them are very beautiful….”

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