From official records we learn that the section of the country in which Cave-in-Rock is embraced was sold, in 1803, to the United States by the Kaskaskia tribe. In 1818, when the sale was confirmed by the same Indians and the three other tribes then constituting the Illinois confederacy, it became unchallenged government property. Thus, when the Masons, the Harpes, and other early outlaws held forth there, it was still in the Indians’ territory.
From a geological standpoint, the Cave is evidently nothing more than a prosaic hole in a limestone bluff. In neither the main cave nor the crevices above are there any stalactites or stalagmites, but an incrustation resembling such a formation occurs here and there on the walls. In 1818, Henry R. Schoolcraft, in his Personal Memoirs, says: “The cave itself is a striking object for its large and yawning mouth, but to the geologist presents nothing novel.” Collot, in 1796, expressed the opinion that “it is an excavation made in the rocks by the continual beating of the flood.” In a Report published in 1866, A. H. Worthen, director of the Geological Survey of Illinois, states that “the limestone (St. Louis limestone) is quite cherty and the Cave has probably been formed by the action of water percolating through crevices of the rock and by the eroding influences of the atmosphere.” Neither of these explanations is satisfactory. No other has been found. Cave-in-Rock has the appearance of a section of a large cave that was formed by an underground stream in some remote geological age, and later disconnected, by upheavals, from the other parts of the subterranean passage. Some of the other parts may still exist. Sulphur Springs Cave, four miles southwest of Equality, may be one. Bigsby Cave, eight miles north of Cave-in-Rock, may be another. Hardin County is besprinkled with many sinkholes, the outlets of which are unknown. The “Big Sink,” four miles north of the Cave, covers about one hundred acres. Cave-in-Rock may have been an outlet for some of these sinkholes until upheavals made such drainage impossible.
In early days the virgin forests retarded, to a great extent, the water of the heavy rains, and as a result floods were less frequent and less severe. It is probable that when Cave-in-Rock and the country about were covered with trees the place was damper than now, for the water then slowly seeped down from the tree-covered surface. Nevertheless, it was sufficiently dry to serve as a good shelter not only for outlaws, who frequently occupied it, but also for men and women going down the river in flatboats.
Today it is comparatively dry, except during the spring and shortly after a heavy rain. Practically all the water running through the Cave now comes from a narrow crevice in the rear, which drains a small sinkhole in the surface. Through this opening, as already stated, much soil has been deposited in the back part of the Cave during the past fifty years. Nature has made practically no changes in the Cave itself since its discovery by white men, but the landscape has been affected by the removal of the large trees that once shaded its mouth. A decrepit sycamore, an ash or two, a few small maple trees, some scrub cedars, and some Virginia creeper constitute the only vegetation now growing around the opening.
The travelers who visited Cave-in-Rock in flatboat days gave the place more time and thought than did those who appeared after the introduction of steamboats. The New Orleans, or Orleans, which was the first steam-propelled boat to make a trip from Pittsburgh to New Orleans, passed it in 1811. Not until fully five years thereafter was the practicability of navigating the Ohio by steamboats satisfactorily demonstrated. Local tradition has it that the James Monroe, coming down in 1816, was the first steamboat to land at the Cave. Thomas Nuttall, who appeared on the scene two years later, was, as already stated, one of the last distinguished men who floated down the river in a flatboat and commented on the place. Leisure was an inseparable feature of flatboat travel. With the coming of steamboats the lingering of travelers along the river became a thing of the past. After 1820 comparatively few boats of any kind stopped at the Cave. Boats became more numerous, but whether propelled by steam or oars, they traveled not only faster but through a country rapidly increasing in population, and passengers and crew stopping in this section found better shelter elsewhere. But Cave-in-Rock was ever pointed out as a place that “in days gone by” had been the den of flatboat robbers. Counterfeiters and other outlaws, however, operated in the neighborhood until as late as 1832.
The earliest record of a professional artist making a sketch of the Cave dates back to May, 1819, when Major Stephen H. Long came down the Ohio on the steamer Western Engineer, on his way to his Rocky Mountains exploring expedition. In his notes on “Cave-Inn-Rock or House of Nature” he gives a description of the Cave, and says that Samuel Seymour, the official artist of the expedition, “sketched two views of the entrance.” Edwin James’s account of this expedition contains many of Seymour’s pictures, but none of places east of the Mississippi. Efforts made in Washington to locate his original sketches were without success.
Edmund Flagg, a traveler, journalist, and poet, who lived the greater part of his life in Louisville and St. Louis, spent a short time at the Cave in 1836, while on a steamboat trip gathering material for his book, The Far West. He gives some of the history of the outlaws of “Cave-Inn-Rock” and then describes the Cave and the Island. He says the place furnishes “a scene of natural beauty worthy an Inman’s pencil” and that “if I mistake not an engraving of the spot has been published: a ferocious-looking personage, pistol in hand, crouched at the entrance, eagerly watching a descending boat.”
Interior of Cave-in-Rock about 1825
A view from the rear of the lower cave, showing burned embers on floor, notched log (on left) leading to upper cave, and flatboats on the river