File:Adventures with animals and plants (1948) (17941224961).jpg

Title: Adventures with animals and plants
Identifier: adventureswithan00kroe (find matches)
Year: 1948 (1940s)
Authors: Kroeber, Elsbeth, 1882-; Wolff, Walter Harold, 1901-
Subjects: Biology
Publisher: Boston : D. C. Heath
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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PROBLEM 2. We Learn of Prehistoric Living Things from Fossils 537 1
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Fig. 488 How one artist pictures a landscape during the age of reptiles. Tyranno- saurus rex and the three-horned dinosaur, Triceratops horridus. (American museum OF NATURAL fflSTORY) crawled over the earth. There were very few reptiles. Certain kinds of insects ex- isted in enormous numbers, huge dragon- flies with a wingspread of a foot, and cockroaches three to four inches long. Toward the close of the Carboniferous period the earth must have sunk in many of the swampy regions. The plants died and were covered by water and then by sediments that eroded from higher ground. Then chemical changes, together with pressure and heat, changed the sub- merged plants to coal. It took millions of years to make the coal; meanwhile more and more sedimentation and rock forma- tion occurred above the coal beds. This happened more than 200 miUion years ago. The Age of Reptiles. This is the fifth (iMesozoic) era. It is believed that it lasted for about 140 million years. The huge evergreens of this era can be seen petrified in Arizona. From the fossil evi- dence, there were reptiles of many spe- cies on the land, in the sea, and in the air. A few kinds of small mammals were in existence and some strange birds had ap- peared. Representatives of the other groups, the fishes and the many types of invertebrates were in existence still, but by far the most numerous among animals were the reptiles, both in numbers and in species. Toward the close of the era the dragonlike reptiles known as di?JOsaurs flourished. Some species of dinosaurs were small; others gigantic. The thunder lizard (Brontosaimis) reached a length of sixty-six feet. It apparently waded about in swamps and shallow lakes and must have eaten about 300 pounds of plants daily. Although it had an esti- mated weight of more than 70,000

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