But there have been two glacial drifts over a great part of North America, and the second ice-flood scoured the earth in such manner as to frequently uncover the forests and animal remains that were buried by the first great deluge. It is in the region of the Petrified and Fossil Forests that we note the evidence of the truth of this theory; not only in Yellowstone Park, but in the Bad Lands of Dakota, the dry lake basins of the Southwest and, in fact, in nearly every State of the Union. But in Yellowstone Park the remains of petrified trees are particularly numerous, and it is here that we observe the most beautiful specimens of chalcedony lying about in promiscuous profusion, like the ruins of some magnificent palace. Every tree here, overwhelmed by the ice-flood, became, in a thousand years thereafter, a pillar of the most exquisite beauty, and we now examine them with wondering curiosity, then convert them into articles of use and adornment. The same chemical action which changed the forests of this region into gem-like stone, also preserved the bones of many huge creatures which met their death suddenly in this volcanic basin. Here and there specimen relics of gigantic animals may be found in the fossil district east of Yellowstone River, though they are becoming scarce because of the immense quantity that has been carried away by scientific bone collectors and the admirers of curious things during the several years that the park has been a popular resort. In this same district there is a depression or basin, about three hundred yards in diameter, which has received the title of Death Valley, a designation that is appropriately applied because it is not only an ossuary, where the bones of many animals lie about in promiscuous profusion, but such noxious gases emanate from the basin that it is represented as a place where no creature can survive the exhalations for more than a few minutes. ------------------------------------------------------------------------ [Illustration: BASALTIC CAÑON OF THE YELLOWSTONE.—The Basaltic Cañon of the Yellowstone is similar in formation to the Giant’s Causeway of Ireland and Fingal’s Cave of Scotland, but not so pronounced in the columnar outlines. It is much more extensive, however, and equally as interesting and remarkable as either of the above-named natural wonders. The erosion of the rocks and the settling of the debris at the foot of the cliffs have shortened the pillars to a very considerable extent, and made them much less imposing than they were originally, but they are still among the most remarkable natural wonders of the world. ] ------------------------------------------------------------------------ [Illustration: