Post 24910
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After this reviving experience, you should take a look into a few of the tertiary volumes of the grand geological library of the park, and see how God writes history. No technical knowledge is required; only a calm day and a calm mind. Perhaps nowhere else in the Rocky Mountains have the volcanic forces been so busy. More than ten thousand square miles hereabouts have been covered to a depth of at least five thousand feet with material spouted from chasms and craters during the tertiary period, forming broad sheets of basalt, andesite, rhyolite, etc., and marvelous masses of ashes, sand, cinders, and stones now consolidated into conglomerates, charged with the remains of plants and animals that lived in the calm, genial periods that separated the volcanic outbursts.
Perhaps the most interesting and telling of these rocks to the hasty tourist, are those that make up the mass of Amethyst Mountain. On its north side it presents a section two thousand feet high of roughly stratified beds of sand, ashes, and conglomerates coarse and fine, forming the untrimmed edges of a wonderful set of volumes lying on their sides,—books a million years old, well bound, miles in size, with full-page illustrations. On the ledges of this one section we see trunks and stumps of fifteen or twenty ancient forests ranged one above another, standing where they grew, or prostrate and broken like the pillars of ruined temples in desert sands,—a forest fifteen or twenty stories high, the roots of each spread above the tops of the next beneath it, telling wonderful tales of the bygone centuries, with their winters and summers, growth and death, fire, ice, and flood.
There were giants in those days. The largest of the standing opal and agate stumps and prostrate sections of the trunks are from two or three to fifty feet in height or length, and from five to ten feet in diameter; and so perfect is the petrifaction that the annual rings and ducts are clearer and more easily counted than those of living trees, centuries of burial having brightened the records instead of blurring them. They show that the winters of the tertiary period gave as decided a check to vegetable growth as do those of the present time. Some trees favorably located grew rapidly, increasing twenty inches in diameter in as many years, while others of the some species, on poorer soil or overshadowed, increased only two or three inches in the same time.