Volcanic outpourings have ended the life of many extensive Yellowstone forests. In Amethyst Mountain are twelve forests, one above the other, buried at different periods by volcanic eruptions. On top of this mountain the pines and spruces are merrily growing, unmindful of the buried past--of the tragic tree history beneath. Nature forgets. Ages ago, the lowest of these entombed forests grew on the mountain plateau in the sunlight. But a flow of volcanic mud and heavy showers of ashes overwhelmed and buried it, with the trees standing erect. This volcanic material added a layer to the plateau. In the new surface above the buried and forgotten forest, another tree growth flourished and towered. But the volcanoes only slept. Again their fire and ashes filled the sky, and again the forest was overwhelmed. Thus through the ages--through "a million years and a day"--each time the volcanoes slept the pines peeped up, and again their shadows fell upon the desolate lava landscape. At last, twelve or more forests were buried, each as it had stood upon the mountain, and in a layer by itself. The material in these numerous fateful volcanic outpourings raised the summit two thousand feet. It may be that the topmost of these petrified forests was overwhelmed by the Ice King, but a volcano entombed the others. All were petrified, fossilized, or opalized. During the ages that went by, the Lamar River and other factors eroded a wide valley and excavated the edges of these forest ruins. [Illustration: PETRIFIED FORESTS IN AMETHYST MOUNTAIN YELLOWSTONE NATIONAL PARK] This reveals one of the most appealing geological stories ever uncovered--twelve illustrated but unwritten chapters of world-building. The strata of these twelve forests, story above story, show their edges in the precipitous northern face of Amethyst Mountain. Thousands of logs and stumps still partly buried jut and bristle. Apparently there is an enormous area of these buried fossil forests in the northeast part of the Park, and perhaps numerous areas elsewhere in the region. They are also known to exist near the northwest boundary of the Park. Mineralized water circulated through and gradually fossilized the buried trees, changing many to opal. In due time the mud and ashes that buried these trees also turned to stone. Limbs and tops of trees were broken off by the ashes, cinders, and mud that buried each forest. Many tree-trunks were overthrown, but great numbers were entombed as they stood. They are from one to ten feet in diameter, and some were of great height. Many of the remaining stumps project forty feet.