Mammoths and Mastodons
Mammoths and Mastodons
People who study the earth, how it was formed, and how it changes are called geologists. They have found out a lot about how the land, the lakes, and the rivers, that are now parts of Michigan, were formed.
Most of what is now known as Michigan was a large bay of water that spread inland from the ocean. This huge bay geologists now call the Michigan Basin.
The western part of the Upper Peninsula was an ancient mountain range the geologists now call the Killarney Mountains. These were formed as what had once been sea bottom slowly folded upward - probably as slow as an inch or so every century or one hundred years.
As time passes slowly the mountains were eaten away by heat, cold, wind, and rain. This process is called erosion. This eroding material ran into the Michigan Basin. Over many years this material cemented together to form many layers of rock. One place in Michigan to see these layers now is called Pictured Rocks in the Upper Penisula along Lake Superior, east of Munising. Iron particles in the layers give it a reddish-brown color.
Michigan's largest waterfall is formed by water from the Tahquamenon River spilling over these layers of rock. At Tahquamenon Falls in the Upper Peninsula you can see the pretty brown color as the sunlight hits the iron in the rock behind the falls.
Layer after layer were formed as the sea bottom slowly filled in. The sea became smaller and more shallow and the land areas became larger. From about 300 million years ago all of Michigan was raised above the sea.
Then the land that was once warm and grew trees and plants, turned cold. Huge ice masses passed over Michigan. These ice masses were called glaciers and they passed over Michigan four times, one after the other.
The Great Lakes were formed by the movement of the glaciers. The melting of the glaciers eroded weak rock and formed holes that the water from the melting ice gathered into and became the lakes. Also the great weight of all that ice depressed the earth's surface making these areas a place for water to gather.
The strong rock areas became the land of Michigan that we know today. This glacial activity also scooped out the areas now covered by Michigan's many thousands of inland lakes. The largest inland lake in Michigan is Houghton Lake in Roscommon County. It has an area of almost 31 square miles.
Dinosaurs?
Understanding the movement of the glaciers as they passed over Michigan four times is important to the question of why nobody has ever found the remains of dinosaurs in Michigan.
It is possible that there were dinosaurs in the area that is now Michigan. The movement of the glaciers back and forth scraped away the layer of rock that was present during the dinosaur age. This back and forth movement would also have removed any dinosaur remains in the rock. Also, the erosion of the land that was going on during this time may have removed any remains of prehistoric reptiles such as dinosaurs.
The largest and the most awesome mammal fossils found in Michigan belong to the American mastodon and the Jefferson mammoth. Fossils are the hardened remains of a plant or an animal of a former age.
Where can you find vertebrate fossils in Michigan? Vertebrates are animals with backbones. You might possibly be able to find vertebrate fossils in two kinds of places.
Rock quarries in Michigan Basin rocks - where you might find the remains of fishes from 280 to 600 million years ago.
Low lakes and pond areas.
Michigan had many more lakes, ponds and swamps a few thousand years ago after the last glacial ice sheet moved on. These ponds filled slowly with plants forming a cover over gooey muck below. These were called bogs. Small animals may have been able to walk over these bogs without falling through. But large animals like the mammoth and the mastodon would have sank into these ancient bogs and died there.
So far, fossil mastodons and mammoths have been found only in the southern two-thirds of the state of Michigan.
Museums with fossils vertebrate collections in Michigan include university museums in Ann Arbor, East Lansing, Kalamazoo and Mount Pleasant and public museums such as those in in Battle Creek and Grand Rapids.
These creatures were huge, elephant-like mammals known as proboscideans. Proboscis means trunk - like an elephant trunk. These large animals had pillar-like legs, a trunk and large tusks. Tusks are specialized teeth that stick out from the animal's jaw.
The American mastodon is probably the best-known fossil vertebrate from Michigan. Most mastodon remains found in southern Michigan were found in bog deposits. Once these great mammals sunk into the muck they were immediately buried. This made finding their complete fossil bones more likely.
The seven to nine-foot tall mastodon had seven to ten-foot tusks thrust forward and with an upward curve. His body was covered with a golden brown to black coarse hair and an adult male weighed about 6 tons! The mastodon most likely ate leaves and twigs from trees in the forests. The American mastodon became extinct somewhere after 6,000 years ago. To become extinct means to no longer exist, or be.
As of 1962 and stated in Margaret Anne Skeels' report, The Mastodons and Mammoths of Michigan, 163 American mastodon fossils had been found in Michigan.
The Jefferson mammoths are less common Michigan fossils than the American mastodons. The mammoths were larger - full grown they were 13 to 14 feet long and 9 to 14 feet tall. They had four-toed feet, a long slender tusk that curved out and up and a thick trunk. The mammoth also had a hump on the back of his neck. He had long black hair with a brown wooly undercoat.
The mammoths most likely grazed and ate the grasses instead of trees. These animals became extinct around 8,000 years ago. Thirty-two Jefferson mammoth remains have been recorded in Michigan since 1839.
There are the remains of 3 individual mammoths in the Grand Rapids Public Museum, 7 in the Michigan State University Museum and 9 in the University of Michigan Museum of Paleontology.
As we mentioned before walrus and whale fossils have also been found in Michigan. They most likely wandered into the Great Lakes after the glaciers left when the rivers flowing from the lakes to the Atlantic Ocean were very high and very deep. They probably did not live for very long in the Great Lakes because the food they needed wasn't there for them.
More information about fossil finds in Michigan can be found in Michigan's Fossil Vertebrates by J. Alan Holman and illustrated by Merald Clark and Barbra Gudgeon. This bulletin was published by the museum at the Michigan State University, 1975.
bogs - lakes and ponds that slowly filled with plants forming a thick layer of these plants over gooey muck.
erosion - the process where land is eaten away by heat, cold, wind, and rain
extinct - to no longer exist, or be
fossils - the hardened remains of a plant or animal of a former age
geologist - people who study the earth, how it was formed and how it changes
glacier - huge ice masses
proboscis - a trunk, like an elephant's trunk
tusk - specialized teeth that stick out from an animal's jaw
vertebrate - animals with backbones
Dunbar, Willis F and May, George S., Michigan: A History of the Wolverine State, William B. Eerdmans Publishing Co., Grand Rapids, MI, 1995.
Homan, J. Alan, Michigan's Fossil Vertebrates, Museum of Michigan State University, 1975.
Lewis, ferris E., My State and Its Story - 13th Edition, Hillsdale School supply Co., Inc., Hillsdale, MI, 1937-1965.
