Part 1: In a Nutshell

  • The earth is about 4.5 billion years old.
  • The geological calendar is divided into four time periods called eras.
  • The Precambrian Era lasted about 4 billion years.
  • The Paleozoic Era lasted about 292 million years.
  • The Mesozoic Era lasted about 183 million years.
  • The Cenozoic Era has lasted about 65 million years, and we are still in this era now.
  • The Cenozoic Era is divided into the Tertiary and Quaternary Periods. (We are in the Quaternary Period of the Cenozoic Era.)
  • Petroleum, coal, and natural gas are called fossil fuels because they were formed from the fossilized remains of plants or animals.
  • The Mesozoic Era has been called the “Age of Reptiles.” Dinosaurs lived during the Mesozoic Era.
  • Fossils from more than a dozen different kinds of dinosaurs have been found in North Dakota.
  • The most common dinosaur found in North Dakota was Triceratops. It could weigh five tons.
  • Tyrannosaurus rex could weigh six tons, but its arms were only about three feet long.
  • Tyrannosaurus rex could eat 500 pounds of meat in one bite.
  • No person has ever seen a dinosaur because they were all extinct before humans lived on the earth.
  • North Dakota was once a hot area with palm trees and tropical flowers.
  • North Dakota once had thick forests with giant trees such as redwoods and sequoias.
  • Ancient trees and other plants became coal.
  • The kind of coal formed in North Dakota is called “lignite.”
  • The earth was probably struck by an asteroid 65 million years ago, killing most animals and plants.
  • The Cenozoic Era has been called the “Age of Mammals.”
  • Petrified wood looks exactly like the plant that had been there in the first place, except it is stone.
  • Western North Dakota has “petrified forests” that contain petrified stumps and logs.
  • The Quaternary Period of the Cenozoic Era has been called the “Ice Age.”
  • Glaciers covered North Dakota more than 20 times.
  • The Wisconsinan glacier was the last glacier to move over North Dakota and stayed here for about 28,000 years.
  • The Wisconsinan glacier covered all of North Dakota except for the southwest corner.
  • Lake Agassiz was formed because glaciers in Canada formed a dam blocking the rivers flowing from the south so they backed up and formed a gigantic lake.
  • Lake Agassiz was 700 miles long, 200 miles wide, and 300 feet deep.
  • Lake Agassiz existed for about 4,000 years.
  • The Red River Valley is the lake bed of the ancient Lake Agassiz.
  • Mastodons and woolly mammoths lived in North Dakota about 11,000 years ago.
  • The area of the state not touched by the Wisconsinan glacier is called the Badlands.
  • Red rock formed from lignite coal burning underground is called “clinker” or “scoria."