there are occasional rifts in the sides, no human being, however skilful as a spire-climber, can ever accomplish its ascent. ------------------------------------------------------------------------ [Illustration: THE DEVIL’S TOWER OF VITRIFIED ROCK, 800 FEET HIGH.—This unparalleled curiosity, the most wonderful formation of the kind in the world, is situated on the bank of Belle Fourche River, in Northeastern Wyoming. It has a base of only 326 feet, and towers to the amazing height of 800 feet above the level plain on which it stands. A full description of this marvelous wonder is given in preceding pages, also an account of the author’s visit to it, when it was specially photographed for GLIMPSES OF AMERICA. ] ------------------------------------------------------------------------ [Illustration: TEA-TABLE ROCK, WISCONSIN RIVER.] The enquiry is irresistible: “What wondrous force created this petrified monster of the Wyoming table-lands?” One plausible answer may be built upon the theory that here, at one time, was the bed of an ocean, a supposition supported by such evidences as the finding of sea-shells and bones of extinct sea-creatures all about over the ground, and deeply embedded in the earth throughout the section. When the waters receded, this inequality, which might have existed as an island, was left as the product of volcanic action. But a yet more reasonable cause may be found in the supposition that along the Belle Fourche was the center of intense volcanic energy sometime during the very remote past, during which period the spot occupied by the tower was a volcano-vent out of which poured lava in such a slow and steady flow that it deposited in basaltic columnar crystals at the apex. Thus gradually it grew in size and height, like many of the formations in Yellowstone Park, until the volcano had expended its force and left this vast monument as an everlasting evidence of its persistence through centuries of activity. But however it was formed, the Devil’s Tower takes a place in the first list of the world’s greatest natural wonders, and it deserves to be much better known than it is.