Mesozoic Era is the age of the dinosaurs, the "middle" time era in the earth's history. It lasted about 125 million years, between the Paleozoic era of ancient life and the Cenozoic era of modern plant and animal life.
A long period of erosion was folio wed by great floods. Mountain building began along the Pacific Coast from Alaska to South America. Fines and flowering plants were new developments. Reptiles were the most important form of animal life in numbers and in kinds. Insects and the first gliding birds appeared. Mesozoic rock layers formed the source of the Gulf Coast, Arabian and Venezuelan oil.
Triassic Period was the earliest of the time periods known for the "red beds" or the red sediment deposited on the land areas through erosion. Volcanoes occurred throughout the Southern Hemisphere and in Brazil there was an immense area of lava rock. The Hudson River Palisades are a Triassic formation and the petrified forest in Arizona shows the cone-bearing trees of this period.
The cold seas at first limited marine life, but later mollusks, clams and oysters, starfish and sea urchins were present. The first turtles and the first reptiles (the Codonts) adapted to life on land are the important new animal forms. In August of 1960 three high school boys digging in a Triassic rock quarry near New York City found an unusual fossil thought to be the very first gliding reptile, older by 30 million years than other finds.
During the Jurassic Period, continued erosion, the formation of fresh water lakes and of coal beds occurred. The seas contained the first true crabs, barnacles and increasing animal life. dinosaurs dominated the land and grew to huge sizes. This is sometimes called the age of the cycads for these palm-like plants occurred abundantly. The gingko may be the oldest of the seed plants living today. There were also true pines and sequoias.
During the 70 million year Cretaceous Period great flooding cut North America into two islands, east and west; the Gulf of Mexico reached nearly to the Ohio river. Volcanoes and folding began the uplift that continued for millions of years to form the Cordillera mountain chain through both Americas.
Marine animals increasingly became mobile and equipped with claws and teeth for more efficient food getting. Flowering plants (angiosperms) were the new forms of plant life. With them came the development of insects. A wasp nest fossil dating back to this time has been found. This period marks the end of the dinosaurs and the increase in mammals.
