Chapter 18: Amazing Ice: Glaciers and Ice Ages
Feature Articles
1: The Discovery of Pleistocene Mammals
2: A Speedy Glacier Teaches Geologists a Lesson
The Discovery of Pleistocene Mammals
by Stephen Marshak
Shown here is a plaster cast scull of Dinotherium giganteum. These ancient relatives of the modern elephant inhabited Earth from the Miocene into the Pleistocene. They reached a height of 4 m (13 feet) at the shoulders, and used their tusks to uproot plants.
Credit: Stephen Marshak
As early as the 1600s, scholars were arguing over the meaning of enormous bones found in sedimentary deposits in Europe. Most thought the bones were relicts of giant humans that had been drowned in Noah's flood. But in 1796, the French anatomist Georges Cuvier used his detailed knowledge of anatomy to show that these giant bones instead resembled those of elephants but were not the bones of any elephant species then alive. Since no one had ever seen these elephants and it seemed unlikely that they could be hiding anywhere, Cuvier reasoned that they must be extinct. The concept seemed outrageous to people of Cuvier's time, who could think of no reason for extinction to occur.
In the early 1800s, explorers discovered still more bones of extinct mammals: cave bears, giant lions, hyenas, and saber-toothed cats. Construction workers even unearthed hippopotamus bones in glacial drift beneath London. The final documentation of Pleistocene mammals came in the early twentieth century, when several Russian expeditions found wooly mammoths that had been frozen intact in the Siberian ice. Much of the mammoth's skin, hair, and flesh remained, and their 30,000-year-old meat was still edible (as far as the sled doges were concerned).
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