What was North America like in the Mesozoic era?
The age old story of the earth dates back more than 4 billion years, and the age old story of life dates back some 2 billion years. Geologists divide the unfolding record of lffe into five eras, like the chapters in a story book. The fourth chapter was the mesozoic era. If we could go back to the start of the mesozoic era, we might think we had landed on another planet. Certainly we would not recognize our north america. But the great era spanned 125 million years, and during that time our land was reshaped” many times. The population of plants and animals also changed. As it ended some 60 million years ago, North America was very much like the land a re know today. When the Mesozoic era opened, North and South America were separated by an aim of the sea. Volcanoes seethed among the eastern Appalachians, and there were no mountains in the west. The western picture changed as the Sierra Nevadas arose, taking millions of years to reach their full height. Later, the California region was
