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      THE STORY TOLD BY THE ROCKS

       Table of Contents

      A BRIEF HISTORY OF SOUTH DAKOTA

       Table of Contents

      CHAPTER I

      THE STORY TOLD BY THE ROCKS

      It is very easy to read the story of the rocks in South Dakota, for here more than anywhere else the several formations are exposed to view: and we can readily see what must have happened in that time very long ago, before men, or even animals, inhabited the Dakota land. The rock formations can be seen more or less all over the state, but their story is clearly shown especially in that section near the head waters of the White River at the foot of the Black Hills, known as the Bad Lands.

      We learn there that in an ancient time a great ocean rolled over South Dakota; that some great convulsion must have occurred deep in the earth which threw up the Black Hills and other western mountains; that the ocean swept over these hills, grinding them up and washing them down across its floor toward the eastern part of the state, thus laying down a formation or stratum now compressed into hard rock which is the lowest of the many formations studied by the geologist. We learn that again and again the rocks and hills were raised up, each time to be ​washed down by the ocean, each washing making a new stratum, until finally there came a time when the ocean could not overcome the hills and the latter became high and solid earth somewhat as we now know them. In this time the earliest evidences of life appeared, in the form of snails and other low orders of creatures.

      Then the ocean seems to have come back and swept down another stratum of soil from the mountain bases, and after it had again subsided came a race of monstrous reptiles, the remains of which are found quite generally over the state wherever the formation of that period is exposed. It is quite certain that at this time South Dakota was in the main a vast steaming swamp, for the climate was tropical, and out of the swamp grew tropical verdure.

      For how long the reptiles reigned no one can ever know, but their period was followed by another, in which great animals, much larger than anything now in existence, roamed throughout the land. They have been given hard names by scientific men who study their remains; as titanotheres, brontotheres, and eleotheres. The titanotheres and brontotheres

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