The Story of the Rocks

The waters of that ocean had gradually invaded most of the land, creeping in stealthily its some places and in others with the force and power of a mighty torrent. The high Ozark Mountains of Missouri kept their heads above the water,, but few indeed were the other spots left unsubmerged in this vast area. This ocean deposited a layer of clean white sand now called Saint Peter Sandstone. Ages later the waters receded, then returned and once again retreated in their never-ending battle with the land

For a time—perhaps a hundred thousand years or more—plants took root and flourished in the soft sands. The climate was tropical, warm, and sultry all the year round. Great fern-like trees sprang up; mosses as high as a man’s waist grew in their shade. But this was not for long. The seas returned, depositing their layer, of sand over this luxuriant vegetation, forcing it into compact lavers, from a foot tot eighteen inches thick. As more sand settled ins these layers of vegetation its the many years that followed, they turned into coal.

Rock Layers that Tell...

The pre-historic ocean that deposited the sand entered the valley many times. Some idea of the number of times it covered the site of Starved lock can be gained by counting the various strata of the rock and its surrounding cliffs.

Only a million years ago—a comparatively recent period as geologists measure time—the earth grew steadily colder. This change did not take place abruptly, but over a period of many thousand years. It began to snow during the winters. Each year it snowed more, and the snow stayed longer. Then came the first great glacier, pressing clown from the frozen north, a mountain of ice that extended as far as the eye could see—had there been men or animals to see it. After several thousand years this glacier began to melt, and its icy waters loured down the valley of the Illinois River.

Several such glaciers moved down from the north, covering Starved Rock with sheets of ice several hundred feet thick. When they melted their waters flowed down the valley, cutting through the softer parts of the sandstone and leaving the harder portions to form the fantastic shapes we now see in the park.

Even the canyons were cut by the rush of glacial waters as they tossed and churned on their way to the Gulf of Mexico. Each spring the waters spread out over the plains, then cut their way back to the river. Heavy rains and thawing winter snows also contributed to the torrents that washed away the rocks. Waterfalls were formed where hard, cemented layers of stone gave way to soft sand that was easily washed away. The process has not ceased. The little rivulets that now flow in the canyons imperceptibly but constantly wear away the rock over which they flow.

The many caves in the bluffs were formed by streams of water that forced their way under the rock, undermining the cliffs. The over-hanging rocks fell when their supports had been washed away, leaving caves that provided shelters for the earliest inhabitants of the valley. Most of these caves are small, but one, Council Cave, is large enough to permit a thousand persons to stand beneath its sheltering roof.

The ancestor of the Illinois River that carried the torrents of glacial waters was more than a mile wide and extended from bluff to bluff. At one time it covered the broad flood-plain on the northern shore; now it is a small stream, occupying only a small portion of its former bed. Once, in its early days, it was strong enough to send its eddies between the rock and the bluff, carving out tine valleys that separate Starved Rock from the bluffs.

...the Story of the Rocks.

The trees and flowers that thrive in tire park are all native to Illinois. The oldest trees in the park are white pines, reminders of a day when once these towering giants were lords of the soil. Oaks, maples, elms, and many other species now predominate where once the pines were most common. Bushes of all kind, known in Illinois thrive ]it the moist sandy earth. Ferns with great broad fronds cling to rocky ledges where even a bird could not rest. The forest floor is covered with wild flowers of all the varied hues of the rainbow. The delicately shaded columbine with its red and white flowers may he seen in any canyon and along any of tit, wooded paths. The foxglove, too, grows in profusion. Protected from drought by the porous sandstone which ever yields it, moisture to plants, these and a thousand other flowers bloom at Starved Rock every year.

Where now the squirrel scampers to bury its food, once roamed more ferocious animals in search of their prey. Wildcats, bear, and wolves had their hiding places in these words. Buffaloes and deer were the first citizens of this state of nature. Along the waterfront and in the swamps were the mounds of muskrats and the darns of beavers. These, however, are long gone. The Indians hunted them and reduced their numbers and the steady push of the first settlers drove them to the farther west. Only those animals titan can live in friendship with man have survived.

Frenchmen visiting the Illinois valley in tire seventeenth century mentioned the brilliantly colored paroquets that lived lure at that time. Today these are no longer seen, but the little wren is still merry with song and the cardinal is a spot of red in the tree. The red-winged blackbird, the scarlet tanager, the canary, and the blue-jay lend their colors to the bird-life in which the park abounds.