And having reached this ancient burial-ground by all these various lines of travel, what do we find here? Stoop and gather a handful of these little gray stones--small pebbles did you call them? The frost and rain of the past winter have washed away the sand and light soil which had hidden them. Why! these are shells, not pebbles. Stone shells, fossil shells! See how perfect every delicate fluting is, how sharply the hinge of the long-perished bivalve is defined. Some are of a delicate pale gray, others almost white; but long ago in the Silurian seas perhaps they shone in brown and yellow, red, pink, buff, and maroon, as gaily as the scallop shells of to-day, which in shape they much resemble. What is this lump of stone covered with little star-shaped knobs? Trace the lines along the side where it was broken from some larger fragment, and they seem to branch; is it like the veins on a leaf? No; rather like the branches of coral, and in fact that is just what we have found,--a lump of fossilized coral of the Silurian age. The lower-Silurian was the age when coral was king. When after the two earlier epochs with their meagre fauna the Silurian age opened, suddenly the seas swarmed with life. They were warm tropic seas, warmer than any on the globe to-day, and in them these industrious coral-polyps built their towers. They built up from the sea-bottom to sunshine, and from each of these star-like towers a living creature unfurled itself like a flower, just beneath the surface of the sea. In orange, scarlet, purple, white, and pink, they expanded their coronals of filaments, and waved to and fro with the warm tides. No flower-garden ever bloomed more gorgeously than did these gardens of the sea in the Silurian age. Plume-like, fine as the stamens of a flower, these myriads of living things leaned from the towers and palaces themselves had built, and drank and fished in these clear seas under the glow of the sun. Meanwhile among and around about these coral towers, cuttle-fish and nautili darted, while mailed crustaceans chased each other, fought and frolicked and devoured each other. See, we have another fossil in the rock, the beautiful stone lilies; they must have a chapter to themselves; and here again are lamp shells and other and different mollusks of the Silurian time. Here they were crowded, swimming and playing in these living coral bowers. How they were dashed by thousands upon this beach of sand! And by and by when life was in its prime, what strange mishaps overtook them all? Did the seas grow too hot or too cold? Did the bed of ocean rise? Did great sand-waves roll in among the coral bowers? They had had their day, another age was drawing on; there would be mollusks and crabs and crustaceans still, but these must perish and be locked up in this burial-ground. O gnomes and genii, keep your treasures well! FOOTNOTES: [28] Pay-lee-o-zo-ic. LESSON XIII. WRITTEN IN ROCKS.