In the vicinity of Cape Girardeau commences what is termed the "Tyowapity Bottom," a celebrated section of country extending along the Missouri side of the stream some thirty miles, and abounding with a peculiar species of potter's clay, unctuous in its nature, exceedingly pure and white, and plastic under the wheel.[52] This stratum of clay is said to vary from one foot to ten in depth, resting upon sandstone, and covered by limestone abounding in petrifactions. A manufactory is in operation at Cape Girardeau, in which this substance is the material employed. Near the northern extremity of this bottom the waters of the Muddy River enter the Mississippi from Illinois.[53] This stream was discovered by the early French voyageurs, and from them received the name of _Rivière au Vase_, or _Vaseux_. It is distinguished for the salines upon its banks, for its exhaustless beds of bituminous coal, for the fertility of the soil, and for a singularly-formed eminence among the bluffs of the Mississippi, a few miles from its mouth. Its name is "_Fountain Bluff_," derived from the circumstance that from its base gush out a number of limpid springs.[54] It is said to measure eight miles {59} in circumference, and to have an altitude of several hundred feet. Its western declivity looks down upon the river, and its northern side is a precipitous crag, while that upon the south slopes away to a fertile plain, sprinkled with farms. A few miles above the Big Muddy stands out from the Missouri shore a huge perpendicular column of limestone, of cylindrical formation, about one hundred feet in circumference at the base, and in height one hundred and fifty feet, called the "Grand Tower."[55] Upon its summit rests a thin stratum of vegetable mould, supporting a shaggy crown of rifted cedars, rocking in every blast that sweeps the stream, whose turbid current boils, and chafes, and rages at the obstruction below. This is the first of that celebrated range of heights upon the Mississippi usually pointed out to the tourist, springing in isolated masses from the river's brink upon either side, and presenting to the eye a succession of objects singularly grotesque. There are said to exist, at this point upon the Mississippi, indications of a huge parapet of limestone having once extended across the stream, which must have formed a tremendous cataract, and effectually inundated all the alluvion above. At low stages of the water ragged shelves, which render the navigation dangerous, are still to be seen. Among the other cliffs along this precipitous range which have received names from the boatmen are the "Devil's Oven," "Teatable," "Backbone," &c., which, with the "Devil's Anvil," "Devil's Island," &c., indicate pretty plainly the divinity most religiously propitiated {60} in these dangerous passes.[56] The "Oven" consists of an enormous promontory of rock, about one hundred feet from the surface of the river, with a