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HTMLText_02718129_88C1_23BF_4163_999EEAE1191A.html = GLACIER
Between 20,000 and 10,000 years ago, glaciers known as the Laurentide Ice Sheet moved across much of Wisconsin, changing the entire landscape. Scientists believe some glaciers may have been more than one mile thick and so heavy that the continental plates beneath them sagged under the mass/weight of the ice. When they melted and retreated back north, the Great Lakes were formed. Other features include landscape formations like moraines, drumlins, and kames. Wisconsin’s bedrock is still to this day rebounding from the weight of the glaciers.
GLACIER
Between 20,000 and 10,000 years ago, glaciers known as the Laurentide Ice Sheet moved across much of Wisconsin, changing the entire landscape. Scientists believe some glaciers may have been more than one mile thick and so heavy that the continental plates beneath them sagged under the mass/weight of the ice. When they melted and retreated back north, the Great Lakes were formed. Other features include landscape formations like moraines, drumlins, and kames. Wisconsin’s bedrock is still to this day rebounding from the weight of the glaciers.
COLONIZATION OF LAND
For billions of years, from the early stromatolites through each window you have already passed, life on Earth has been going through the process of evolution. Evolution is when organisms develop and diversify, eventually creating new species.
This window displays the evolution of plants on land. Although plants evolved after animals, they actually made it to and first.
To learn more about the scientist who first theorized evolution, Charles Darwin, click on the video icon in the exhibit.
They began as small, leafless structures and eventually evolved into towering trees. Like the cyanobacteria, they would have a major impact on Earth’s atmosphere.
Some animals, drawn to this new food source, eventuall evolved to live on land, leading the way for the diversity of life above water.
COLONIZATION OF LAND
For billions of years, from the early stromatolites through each window you have already passed, life on Earth has been going through the process of evolution. Evolution is when organisms develop and diversify, eventually creating new species.
This window displays the evolution of plants on land. Although plants evolved after animals, they actually made it to and first.
To learn more about the scientist who first theorized evolution, Charles Darwin, click on the video icon in the exhibit.
They began as small, leafless structures and eventually evolved into towering trees. Like the cyanobacteria, they would have a major impact on Earth’s atmosphere.
Some animals, drawn to this new food source, eventuall evolved to live on land, leading the way for the diversity of life above water.
HERBIVORES AND CARNIVORES
This exhibit shows a variety of herbivores (plant-eaters) and carnivores (meat-eaters). Click on the icon below to download a quick game to help you identify which is which.
HERBIVORES AND CARNIVORES
This exhibit shows a variety of herbivores (plant-eaters) and carnivores (meat-eaters). Click on the icon below to download a quick game to help you identify which is which.
Fluorite
Crystals
3D Photogrammetry by Dr. Ralph L. Kugler
Fluorite
Crystals
3D Photogrammetry by Dr. Ralph L. Kugler
COLBY METEORITE
• Stony condrite consisting of olivine and hypersthene
• Fell in Colby, Clark County, Wisconsin on 4 July 1917 at 6:20 pm
• Weight of this sample is 417.9 grams
3D photogrammetry by Dr. Ralph L. Kugler
COLBY METEORITE
• Stony condrite consisting of olivine and hypersthene
• Fell in Colby, Clark County, Wisconsin on 4 July 1917 at 6:20 pm
• Weight of this sample is 417.9 grams
3D photogrammetry by Dr. Ralph L. Kugler
CALYMENE NIAGARENSIS
Trilobite
• Hawthorne, Illinois USA
• Collected by Thomas Greene - 3 April 1909
• Trilobite is 20mm long
• MPM Collections No. P723
• MPM Locality No. 30039
3D Photogrammetry by Dr. Ralph L. Kugler
648 photographs used to make this model
CALYMENE NIAGARENSIS
Trilobite
• Hawthorne, Illinois USA
• Collected by Thomas Greene - 3 April 1909
• Trilobite is 20mm long
• MPM Collections No. P723
• MPM Locality No. 30039
3D Photogrammetry by Dr. Ralph L. Kugler
648 photographs used to make this model
Welcome to MPM’s
A Tribute to Survival.
This exhibit is meant to serve as an introduction to our larger Native American galleries. The overarching message of this exhibit is that Native Americans are still here and have survived and thrived against many attempts to eradicate and assimilate them into the dominant society. The exhibit stands as a testament to their resilience.
As you explore this exhibit, you’ll notice differently colored text on some labels. The words in blue represent the Native American voice, while the words in white represent the academic voice.
Welcome to MPM’s
A Tribute to Survival.
This exhibit is meant to serve as an introduction to our larger Native American galleries. The overarching message of this exhibit is that Native Americans are still here and have survived and thrived against many attempts to eradicate and assimilate them into the dominant society. The exhibit stands as a testament to their resilience.
As you explore this exhibit, you’ll notice differently colored text on some labels. The words in blue represent the Native American voice, while the words in white represent the academic voice.
Dinosaur
PACHYCEPHALOSAUR SKULL
(Ornithischia)
This specimen was recovered in 1985 as part of a former MPM citizen science program called Dig-A-Dino. This program was focused on dinosaur abundance and diversity at the end of the Cretaceous period, with a particular focus on the Hell Creek Formation. The specimen here, VP 7111, is assigned as Stygimoloch spinifer and is one of two pachycephalus skulls housed within our collections. Both of these specimens have been studied to understand the anatomy and physiology of these dome-skulled dinosaurs. Studying these specimens, paleontologists have refined their understanding of the behaviors from these dinosaurs, and that their skulls were most likely used for display behaviors (think brightly colored feathers of birds) rather than for headbutting and territorial behaviors.
3D Photogrammetry by Dr. Ralph L. Kugler
Dinosaur
PACHYCEPHALOSAUR SKULL
(Ornithischia)
This specimen was recovered in 1985 as part of a former MPM citizen science program called Dig-A-Dino. This program was focused on dinosaur abundance and diversity at the end of the Cretaceous period, with a particular focus on the Hell Creek Formation. The specimen here, VP 7111, is assigned as Stygimoloch spinifer and is one of two pachycephalus skulls housed within our collections. Both of these specimens have been studied to understand the anatomy and physiology of these dome-skulled dinosaurs. Studying these specimens, paleontologists have refined their understanding of the behaviors from these dinosaurs, and that their skulls were most likely used for display behaviors (think brightly colored feathers of birds) rather than for headbutting and territorial behaviors.
3D Photogrammetry by Dr. Ralph L. Kugler
CALENDAR
This calendar imagines the history of Earth, from its formation to today, if it were compressed into just 30 days. Each day represents 150 million years. By condensing geologic time this way, we learn that humans have only been around for two minutes of Earth’s entire “30-day” history
CALENDAR
This calendar imagines the history of Earth, from its formation to today, if it were compressed into just 30 days. Each day represents 150 million years. By condensing geologic time this way, we learn that humans have only been around for two minutes of Earth’s entire “30-day” history
RELATIVE OF DRAGONFLY
During the Carboniferous period, oxygen in the atmosphere rose to as high as 35%, compared to 20% today. This contributed to a period of insect and amphibian gigantism, whose sizes are constrained by their ability to diffuse oxygen.
RELATIVE OF DRAGONFLY
During the Carboniferous period, oxygen in the atmosphere rose to as high as 35%, compared to 20% today. This contributed to a period of insect and amphibian gigantism, whose sizes are constrained by their ability to diffuse oxygen.
BASALT
Have you wondered what’s beneath the surface of the Earth?
If you guessed rock, you’re right! Magma from the center of the Earth is pushed up into the surface and cooled, making rocks like this that create the crust of the Earth, separating it from the molten core.
There is one place in Wisconsin where you can walk on basaltic lava rock that makes up Earth’s crust – Interstate State Park near St. Croix Falls in Northwest Wisconsin. There, the volcanic basalt has been raised up and exposed to the erosive actions of glaciers and glacial meltwater.
BASALT
Have you wondered what’s beneath the surface of the Earth?
If you guessed rock, you’re right! Magma from the center of the Earth is pushed up into the surface and cooled, making rocks like this that create the crust of the Earth, separating it from the molten core.
There is one place in Wisconsin where you can walk on basaltic lava rock that makes up Earth’s crust – Interstate State Park near St. Croix Falls in Northwest Wisconsin. There, the volcanic basalt has been raised up and exposed to the erosive actions of glaciers and glacial meltwater.
STROMATOLITES
Here, we have a trace fossil called stromatolite. It is evidence of one of the earliest forms of life on Earth – cyanobacteria. About 3.5 billion years ago, cyanobacteria developed the machinery to turn carbon dioxide and water into sugar using sunlight as an energy source. In the process, they released oxygen as a waste product, just like plants. Over time, this transformed the Earth into an oxygen-rich atmosphere, allowing for the emergence of complex lifeforms, including us.
STROMATOLITES
Here, we have a trace fossil called stromatolite. It is evidence of one of the earliest forms of life on Earth – cyanobacteria. About 3.5 billion years ago, cyanobacteria developed the machinery to turn carbon dioxide and water into sugar using sunlight as an energy source. In the process, they released oxygen as a waste product, just like plants. Over time, this transformed the Earth into an oxygen-rich atmosphere, allowing for the emergence of complex lifeforms, including us.
MAMMOTH
Mammoth or Mastodon?
Mammoths and mastodons are two extinct species that once roamed Wisconsin. Although they look similar, they are actually part of two different families. Mammoths belong to the same family as modern-day elephants, whereas the mastodons were part of their own family that is now extinct.
How can you tell the difference?
Mastodons were smaller, with flatter heads. Mammoths had a rounder head as well as humps on their backs.
But the biggest difference between these animals is in their teeth and jaws. Mammoths and mastodons were both herbivores, but differences in diets required different teeth.
Mastodon jaws were longer with three molars on each side on both the top and bottom. Their teeth had cone-shaped cusps on their molars that allowed them to crush hard twigs and branches, which made up a large portion of their diet.
Mammoths were grazers and had flatter teeth that allowed them to grind coarse vegetation such as grass and shrubs. A fun fact about mammoth teeth: They would wear down and be replaced five times in a mammoth’s life, which means they were born with six sets of teeth.
A mammoth fossil known as the Hebior Mammoth, found in Kenosha, Wisconsin, shows cut marks, confirming the existence of humans in Wisconsin as early as 14,500 years ago.
Click on the link icon to see the Hebior Mammoth on the MPM web page.
MAMMOTH
Mammoth or Mastodon?
Mammoths and mastodons are two extinct species that once roamed Wisconsin. Although they look similar, they are actually part of two different families. Mammoths belong to the same family as modern-day elephants, whereas the mastodons were part of their own family that is now extinct.
How can you tell the difference?
Mastodons were smaller, with flatter heads. Mammoths had a rounder head as well as humps on their backs.
But the biggest difference between these animals is in their teeth and jaws. Mammoths and mastodons were both herbivores, but differences in diets required different teeth.
Mastodon jaws were longer with three molars on each side on both the top and bottom. Their teeth had cone-shaped cusps on their molars that allowed them to crush hard twigs and branches, which made up a large portion of their diet.
Mammoths were grazers and had flatter teeth that allowed them to grind coarse vegetation such as grass and shrubs. A fun fact about mammoth teeth: They would wear down and be replaced five times in a mammoth’s life, which means they were born with six sets of teeth.
A mammoth fossil known as the Hebior Mammoth, found in Kenosha, Wisconsin, shows cut marks, confirming the existence of humans in Wisconsin as early as 14,500 years ago.
Click on the link icon to see the Hebior Mammoth on the MPM web page.
DIPLICHNITES
Wisconsin has sandstone like this throughout the state, which holds clues to its past. In MPM’s Geology research collection, a 2,600-pound piece of sandstone discovered in Marathon County, WI shows footprints of an arthropod creature (related to modern-day insects, crustaceans, and spiders) that lived approximately 500 million years ago.
Click the link below to learn more.
DIPLICHNITES
Wisconsin has sandstone like this throughout the state, which holds clues to its past. In MPM’s Geology research collection, a 2,600-pound piece of sandstone discovered in Marathon County, WI shows footprints of an arthropod creature (related to modern-day insects, crustaceans, and spiders) that lived approximately 500 million years ago.
Click the link below to learn more.
REPLICA OF ARCHAEOPTERYX FOSSIL
This is a replica of the Archaeopteryx fossil, believed to be one of the first birds.
Did you know that birds are dinosaurs? Dinosaurs did not “turn into” birds, but rather birds evolved from avian dinosaurs. To think of it another way, compare an extinct mammal, such as a mammoth, and a living mammal, such as an elephant. Both are mammals and look similar, but they are very different and lived at different times. Mammoths, even though extinct, did not turn into elephants, even though both are mammals. Likewise, birds and dinosaurs evolved from the same group.
REPLICA OF ARCHAEOPTERYX FOSSIL
This is a replica of the Archaeopteryx fossil, believed to be one of the first birds.
Did you know that birds are dinosaurs? Dinosaurs did not “turn into” birds, but rather birds evolved from avian dinosaurs. To think of it another way, compare an extinct mammal, such as a mammoth, and a living mammal, such as an elephant. Both are mammals and look similar, but they are very different and lived at different times. Mammoths, even though extinct, did not turn into elephants, even though both are mammals. Likewise, birds and dinosaurs evolved from the same group.
GALENA
This is an example of Galena, a lead sulfide. It was the first metal ore mined in Wisconsin and is the official state mineral of Wisconsin. Lead miners who moved to the southwest part of Wisconsin in the 1820s and 1830s burrowed holes into hillsides for quick homes, earning the miners the nickname "badgers," hence Wisconsin becoming the "Badger State."
GALENA
This is an example of Galena, a lead sulfide. It was the first metal ore mined in Wisconsin and is the official state mineral of Wisconsin. Lead miners who moved to the southwest part of Wisconsin in the 1820s and 1830s burrowed holes into hillsides for quick homes, earning the miners the nickname "badgers," hence Wisconsin becoming the "Badger State."
STALAGMITES, STALACTITES AND COLUMNS
Rocks and magma aren’t solely responsible for how the Earth looks. Water has and continues to shape the landscape every day. Below the ground, water carves out caves like this one. As water drips into the cave, it deposits calcite minerals it picked up traveling through the ground on the same spot over and over again, slowly creating these formations over hundreds of years.
These formations are known as stalactites (which stick tight to the ceiling) and stalagmites (which stand mightily on the ground). When a stalactite and a stalagmite grow large enough to merge, they are known as a column, also shown here.
STALAGMITES, STALACTITES AND COLUMNS
Rocks and magma aren’t solely responsible for how the Earth looks. Water has and continues to shape the landscape every day. Below the ground, water carves out caves like this one. As water drips into the cave, it deposits calcite minerals it picked up traveling through the ground on the same spot over and over again, slowly creating these formations over hundreds of years.
These formations are known as stalactites (which stick tight to the ceiling) and stalagmites (which stand mightily on the ground). When a stalactite and a stalagmite grow large enough to merge, they are known as a column, also shown here.
THE CONTINENTS UNDER SIEGE
The background of this window represents the Grand Canyon, which was formed through the process of erosion. Beginning 5-6 million years ago, water from the Colorado River eroded, or wore away, through layers of rock, slowly creating the natural wonder we see today.
THE CONTINENTS UNDER SIEGE
The background of this window represents the Grand Canyon, which was formed through the process of erosion. Beginning 5-6 million years ago, water from the Colorado River eroded, or wore away, through layers of rock, slowly creating the natural wonder we see today.
DINOSAURS IN WISCONSIN?
Most geologists believe dinosaurs did live in what is now Wisconsin, but unfortunately there is no evidence. In fact, that entire layer of our state’s history is missing. During this time period, Wisconsin was probably above sea level, and little was preserved in the rock record. In addition, whatever might have been deposited was ultimately lost due to erosion.
Although popular media tend to show a wide variety of dinosaur species living together, “the age of the dinosaurs” actually spanned 135 million years, which included many extinctions. In fact, Tyrannosaurus rex, which we’ll see in the next exhibit, lived closer in geologic history to humans (which existed 65 million years apart) than it did to this Stegosaurus (which existed 80 million years prior to the T. rex).
DINOSAURS IN WISCONSIN?
Most geologists believe dinosaurs did live in what is now Wisconsin, but unfortunately there is no evidence. In fact, that entire layer of our state’s history is missing. During this time period, Wisconsin was probably above sea level, and little was preserved in the rock record. In addition, whatever might have been deposited was ultimately lost due to erosion.
Although popular media tend to show a wide variety of dinosaur species living together, “the age of the dinosaurs” actually spanned 135 million years, which included many extinctions. In fact, Tyrannosaurus rex, which we’ll see in the next exhibit, lived closer in geologic history to humans (which existed 65 million years apart) than it did to this Stegosaurus (which existed 80 million years prior to the T. rex).
SEISMOGRAPH
The land that is today's Wisconsin wasn’t always located “up north.” This is because beneath the ocean and continents, the Earth’s crust is made up of tectonic plates. The hot magma inside the Earth moves these plates, like water moving a sheet of ice floating on it. Tectonic plates move about as quickly as your fingernails grow. That doesn’t sound like much, but over billions of years, they can move thousands and thousands of miles.
The edges of tectonic plates push or slide against each other, which can create mountains, volcanoes, and earthquakes, like the one recorded in this seismograph.
SEISMOGRAPH
The land that is today's Wisconsin wasn’t always located “up north.” This is because beneath the ocean and continents, the Earth’s crust is made up of tectonic plates. The hot magma inside the Earth moves these plates, like water moving a sheet of ice floating on it. Tectonic plates move about as quickly as your fingernails grow. That doesn’t sound like much, but over billions of years, they can move thousands and thousands of miles.
The edges of tectonic plates push or slide against each other, which can create mountains, volcanoes, and earthquakes, like the one recorded in this seismograph.
PECCARY
This item is on load from The Smithsonian Institution, National Museum of Natural History, Department of Paleobiology. USNM V26098.
You can learn more about this specimen by clicking the link button below
PECCARY
This item is on load from The Smithsonian Institution, National Museum of Natural History, Department of Paleobiology. USNM V26098.
You can learn more about this specimen by clicking the link button below
DROMAEOSAURUS
While there is strong evidence for many species of dinosaurs having feathers, it does not mean that every dinosaur had them. Scientists are still uncovering clues about the evolution of dinosaurs and birds and are making incredible discoveries every year.
Watch a video on Dromaeosaurus by clicking the vidieo icon to the left of this window
DROMAEOSAURUS
While there is strong evidence for many species of dinosaurs having feathers, it does not mean that every dinosaur had them. Scientists are still uncovering clues about the evolution of dinosaurs and birds and are making incredible discoveries every year.
Watch a video on Dromaeosaurus by clicking the vidieo icon to the left of this window
IRISH ELK
This item is on loan from the Smithsonian Institution, National Museum of Natural History, Department of Paleobiology, USNM V 7052
You can learn more about this specimen by clicking the link button below.
IRISH ELK
This item is on loan from the Smithsonian Institution, National Museum of Natural History, Department of Paleobiology, USNM V 7052
You can learn more about this specimen by clicking the link button below.
VIRTUAL SILURIAN REEF
If you were in this exact spot 410 million years ago, you’d probably need some scuba gear!
There are surprisingly no plants in this window. While plants did exist during the Silurian period, they looked very little like any plant today and did not inhabit a reef like the one here.
You can explore the Silurian Sea in detail at the Virtual Silurian Reef site, which was made in partnership with Chicago’s Field Museum by clicking on the link below.
VIRTUAL SILURIAN REEF
If you were in this exact spot 410 million years ago, you’d probably need some scuba gear!
There are surprisingly no plants in this window. While plants did exist during the Silurian period, they looked very little like any plant today and did not inhabit a reef like the one here.
You can explore the Silurian Sea in detail at the Virtual Silurian Reef site, which was made in partnership with Chicago’s Field Museum by clicking on the link below.
Hell Creek Diorama
This exhibit shows a variety of herbivores (plant-eaters) and carnivores (meat-eaters). Click here to download a quick game to help you identify which is which.
Hell Creek Diorama
This exhibit shows a variety of herbivores (plant-eaters) and carnivores (meat-eaters). Click here to download a quick game to help you identify which is which.
TYRANNOSAURUS
The Tyrannosaurus rex, known as T. rex, lived 67-65 million years ago. While its big head and little arms may look goofy, it was actually an adept predator. The jaws had an incredibly strong bite and its skull was developed to withstand great pressure and stress. Scientists who have studied the Tyrannosaurus’s arms have determined that they were strong, well-muscled, and used. It is likely that they held down prey as the jaws did their work.
TYRANNOSAURUS
The Tyrannosaurus rex, known as T. rex, lived 67-65 million years ago. While its big head and little arms may look goofy, it was actually an adept predator. The jaws had an incredibly strong bite and its skull was developed to withstand great pressure and stress. Scientists who have studied the Tyrannosaurus’s arms have determined that they were strong, well-muscled, and used. It is likely that they held down prey as the jaws did their work.
TRICERATOPS
The Triceratops is one of many species of ceratopsians. To learn more about ceratopsians, visit the Torosaur at the beginning of the Third Planet Gallery.
TRICERATOPS
The Triceratops is one of many species of ceratopsians. To learn more about ceratopsians, visit the Torosaur at the beginning of the Third Planet Gallery.
BANDED IRON FORMATION
The Earth didn’t change to an oxygen atmosphere all at once. In fact, the amount of oxygen varied over time, and is evident in this banded iron formation. The conventional concept is that the reddish layers are made of iron and were formed in sea water as the result of oxygen released by primitive photosynthetic bacteria (blue-green algae). Iron combined with oxygen to form iron oxides, which formed a thin, red layer alternating with shale and chert. The alterations are thought to be due to cyclic or seasonal variations in available oxygen.
BANDED IRON FORMATION
The Earth didn’t change to an oxygen atmosphere all at once. In fact, the amount of oxygen varied over time, and is evident in this banded iron formation. The conventional concept is that the reddish layers are made of iron and were formed in sea water as the result of oxygen released by primitive photosynthetic bacteria (blue-green algae). Iron combined with oxygen to form iron oxides, which formed a thin, red layer alternating with shale and chert. The alterations are thought to be due to cyclic or seasonal variations in available oxygen.
WELCOME TO MPM'S
THIRD PLANET GALLERY
Welcome to the Milwaukee Public Museum’s Third Planet gallery! In this exhibit, you’ll explore the formation and geology of Earth along with the evolution of life on the planet. During this self-led tour, you’ll hear from MPM scientists, get close-up looks at behind-the-scenes artifacts, and unlock the secrets of Earth’s 4.5-billion-year history.
WELCOME TO MPM'S
THIRD PLANET GALLERY
Welcome to the Milwaukee Public Museum’s Third Planet gallery! In this exhibit, you’ll explore the formation and geology of Earth along with the evolution of life on the planet. During this self-led tour, you’ll hear from MPM scientists, get close-up looks at behind-the-scenes artifacts, and unlock the secrets of Earth’s 4.5-billion-year history.
LYCOPOD
This case shows fossils from the Carboniferous period. Eventually, these rainforests began to fragment into smaller pieces and were devastated by the drying climate. This led to what is called the Carboniferous rainforest collapse (CRC), a mass-extinction event involving the lycopods. Microscopic analysis suggests that lycophytes make up 70% of the organic matter that formed Carboniferous coal. Coal miners have found the outlines of these trees in their mines.
LYCOPOD
This case shows fossils from the Carboniferous period. Eventually, these rainforests began to fragment into smaller pieces and were devastated by the drying climate. This led to what is called the Carboniferous rainforest collapse (CRC), a mass-extinction event involving the lycopods. Microscopic analysis suggests that lycophytes make up 70% of the organic matter that formed Carboniferous coal. Coal miners have found the outlines of these trees in their mines.
THE GREAT EXTINCTION
Throughout this exhibit’s timeline, millions of species have evolved and gone extinct due to changes in resources, landscape, and climate. The Mesozoic Era came to an abrupt end 66 million years ago and with it the extinction of many animals and plants on land and sea. Non-avian dinosaurs also disappeared from the fossil record after this time. Today, there is agreement that the primary cause of this extinction event was the asteroid that struck Earth and set off a series of catastrophic events.
Evidence of this asteroid is found in stones that have a white band, known as the KT Boundary. Below this band, dinosaur fossils are found; above it, no dinosaur fossils are found. MPM has a wonderful example of this in our collections. You can see a recreation of this boundary in our Exploring Life on Earth exhibit.
THE GREAT EXTINCTION
Throughout this exhibit’s timeline, millions of species have evolved and gone extinct due to changes in resources, landscape, and climate. The Mesozoic Era came to an abrupt end 66 million years ago and with it the extinction of many animals and plants on land and sea. Non-avian dinosaurs also disappeared from the fossil record after this time. Today, there is agreement that the primary cause of this extinction event was the asteroid that struck Earth and set off a series of catastrophic events.
Evidence of this asteroid is found in stones that have a white band, known as the KT Boundary. Below this band, dinosaur fossils are found; above it, no dinosaur fossils are found. MPM has a wonderful example of this in our collections. You can see a recreation of this boundary in our Exploring Life on Earth exhibit.