Rhodinia Pangaea Texas Panspermia Describe the environment found over most of North America during the first three periods of the Paleozoic in terms of water depth and kinds of animals and plants that were fossilized. List the periods of the Paleozoic era, oldest first. At mid-Cenozoic time, South America had a great variety of marsupials, but few placental mammals, and no large predators. Then almost all marsupial species died out. The United States is dependent on foreign coal.
Coal ash is usually toxic.
Sketch any two types of petroleum traps. Indicate which layers are permeable and impermeable. Distinguish fission from fusion.