Browse this collection of fossils from the GRPM Collections. Step back on the geological timeline to explore a variety of fossilized plant and remains.

Megalodon lived 23 million to 3.6 million years ago and is estimated to have attained a maximum body length of 16-18 meters (52-60 feet), making it one of the largest sharks to ever exist!  Megalodon fossils have been found on all continents except Antarctica, indicating it probably had a worldwide distribution.  There is some debate about megalodon’s evolutionary relationship to modern sharks.  Some scientists think megalodon is more closely related to the modern great white sharks, while others think they are more closely related to modern mako sharks.

This tooth was collected circa 2017 from Fossil Ledge (Inner and Outer Reef localities), 25-38 miles off the coast of southeastern North Carolina, near Wilmington, in 80-100 feet of water.

Age of the fossil is estimated to be 6-10 million years old (late Miocene).

Megalodon lived 23 million and 3.6 million years ago and is estimated to have attained a maximum body length of 16-18 meters (52-60 feet), making it one of the largest sharks to ever exist.  It has been found on all continents except Antarctica, indicating it probably had a worldwide distribution.  There is some debate about megalodon’s evolutionary relationship to modern sharks.  Some scientists think megalodon is more closely related to the modern great white sharks, while others think they are more closely related to modern mako sharks.

This tooth was collected in August of 2016, 2017, or 2018 from Fossil Ledge (Inner and Outer Reef localities), 25-38 miles off the coast of southeastern North Carolina, near Wilmington, in 80-100 feet of water.

Age of the fossil is estimated to be 6-10 million years old (late Miocene).

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Grand Rapids Public Museum

Megalodon tooth

Pennsylvanian Period, around 320-390 Million Years Ago 

This specimen is a fossil imprint from the bark of scale trees (lycopods). Scientists have called these trees, scale trees, because their bark looked like a snake’s scales. Records of these trees are common in Michigan’s rock layers and they could grow to be over 100 feet tall! The climate of Michigan 320-390 million years ago was tropical and humid, so the forests then looked very different from the forests we see today. For example, there were no flowering plants during this period and even large trees were not woody like many are today!

This specimen is a fossil imprint from the bark of scale trees known as lycopods. These trees, named after their similar appearance to snake scales, could grow to over 100 feet tall and are commonly found in Michigan's rock layers.

Michigan's climate 320-390 million years ago was tropical and humid so the forests looked very different from Michigan forests we see today. 

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Tree Bark Imprint Fossil

Amber is formed from tree resin that fossilizes over millions of years. Most amber that is found dates to around 30-90 million years ago, although some of the oldest specimens date to 320 million years ago. 

Amber can contain pieces of plants, insects, or other creatures that were trapped in the resin and preserved within the fossil. Due to its appearance, amber has been used in jewelry and prized by the people of many different civilizations over time

Amber is a fossilized tree resin that dates back to 30-90 million years ago with some of the oldest specimens dating to 320 million years ago. It can often contain pieces of plants, insects, or other creatures that were trapped in the resin and preserved. Due to its color and appearance, it is often used in jewelry. 


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Amber

Petrified wood is a special type of fossilized remains of terrestrial vegetation. It results when that vegetation undergoes the process of permineralization, which is when vegetation completely transitions to stone.

When plant material gets buried by sediment it can be protected from oxygen and other living things that would cause it to decay. Over time, dissolved solids carried in groundwater flow through the sediment causing the plant material to be replaced with mineral and other non-living materials. This creates a fossil of the original plant material. 

Petrified wood is a special type of fossilized remains of terrestrial vegetation. It results when that vegetation undergoes the process of permineralization, which is when vegetation completely transitions to stone. 


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Petrified Wood

A siderite concretion that was split open to reveal an impression of a fern. 

Mazon Creek, IL is a famous fossil locality containing plants and animals from 309 million years ago. These fossils formed from a large flooding event that rapidly buried organisms, allowing for soft parts to be preserved.

Many types of plant fossils can also be found in Michigan’s rock layers. Around 320 million years ago, the land that is now Michigan was warm and humid and a wide variety of plants grew here. Ferns were very numerous in Michigan during this time. It is common to find them in the fossil record from this time period.


A siderite concretion that was split open to reveal an impression of a fern (consists of 2 halves, labeled A and B). 

Mazon Creek, IL is a famous fossil locality containing plants and animals from 309 million years ago. These fossils formed from a large flooding event that rapidly buried organisms, allowing for soft parts to be preserved.


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Pecopteris unita

Late Cretaceous Period, 100-66 Million Years Ago

This specimen is a replica cast of the egg of an Oviraptor Philoceratops. The oviraptor Philoceratops was a bird-like dinosaur that lived during the late Cretaceous period around 75 million years ago. Oviraptor eggs are more common in the fossil record than those of other dinosaurs. 

It is thought that these dinosaurs brooded their eggs on the nest to hatch them, similar to the way many bird species do today. 


This specimen is a replica cast of the egg of an Oviraptor Philoceratops. The oviraptor Philoceratops was a bird-like dinosaur that lived during the late Cretaceous period around 75 million years ago. It is thought that these dinosaurs brooded their eggs on the nest to hatch them, similar to the way many bird species do today. 


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Oviraptor Philoceratops Egg Replica

 Pleistocene Epoch, 1.5 Million-10,000 Years Ago

The American mastodon was a large creature, similar to modern-day elephants. The American mastodon lived in Michigan during the Pleistocene Epoch (also known as the ice-age), around 1.5 million years ago to 10,000 years ago. The mastodon was similar in size to a modern-day African elephant, with a shoulder height of 8-9 feet and weight of 4-6 tons. 

This specimen shows how mastodon teeth were sharp and ridged, allowing them to eat a variety of tough plant materials, including twigs, roots, and branches. 

Mastodon fossils are abundant in Michigan, and there have been many exciting new discoveries in recent years, including a nearly complete skeleton in 2014. The mastodon fossil became the official state fossil of Michigan in 2002.

The Ameican Mastodon lived in Michigan during the Pleistocene Epoch, also known as the ice-age, around 1.5 million years ago to 10,000 years ago. It was similar in size to a modern-day African Elephant with a shoulder height of eight to nine feet and a weight of four to six tons. This specimen, which was discovered in Florida, shows how Mastodon teeth were sharp and ridged, allowing them to eat a variety of tough plant material including twigs, roots, and branches.

Mastodon fossils are abundant in Michigan and in 2002, it became the official state fossil. 

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Mastodon Tooth

Cretaceous Period, roughly 83.6-60 Million Years Ago

 tooth from the Hell Creek Formation in South Dakota.  

Tyrannosaurus rex was a carnivore, meaning their diet was made up of meat. The T. rex lived during the Cretaceous period, 83.6 million years ago to 60 million years ago. It was one of the largest meat-eating dinosaurs that ever lived and could grow to 40 feet long and 15-20 feet tall. 

T. rex teeth were serrated (jagged or saw-like) and cone-shaped and most likely used to rip and tear flesh. Scientists think that a single T. rex could eat up to 500 pounds of meat in just one bite!

Cast of a 33 centimeter (13 inches) Tyrannosaurus rex tooth from the Hell Creek Formation in South Dakota.  

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Tyrannosaurus Rex Tooth, cast

Cast of a woolly mammoth molar. The original tooth was  found by a fisherman in the North Sea.

Mammoth's were herbivores, meaning their diet was made up of plants. 

Cast of a woolly mammoth molar purchased from Prehistoric Planet (www.PrehistoricPlanet.com).  The original tooth was supposedly found by a fisherman in the North Sea.


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Woolly Mammoth molar, cast

Trilobites are the earliest known arthropods.  They are related to crustaceans, spiders and other insects that are alive today. 

Their fossil record spans from the early Cambrian (~521 million years old) to the end of the Permian (251 million years ago), but they are not very common after 372 million years ago. Proetidae is a family of Trilobites that are found from 485 to 251 million years ago.  

Trilobite bodies have a cephalon, segmented thorax, pygidium, and have compound eyes. They are only found in saltwater environments.

They crawled along the bottom and some types could swim. Different trilobite species were different sizes. Some of the smallest were only 1 cm long and the largest were 70 cm or longer! 



Trilobites are the earliest known arthropods.  Their fossil record spans from the early Cambrian (~521 million years old) to the end of the Permian (251 million years ago), but they are not very common after 372 million years ago. Trilobite bodies have a cephalon, segmented thorax, pygidium, and have compound eyes. They are only found in saltwater environments.

Proetidae is a family of Trilobites that are found from 485 to 251 million years ago. 

Standards for Fossil Exploration

Next Generation Science Standards