United States Department of Agriculture TOADSTOOL GEOLOGIC PARK OGLALA NATIONAL GRASSLAND, NEBRASKA PREHISTORIC MAMMALS FROZEN IN STONE SEE LEARN FOSSIL TRACKS ALONG BOUT OSSILS AND THE A PREHISTORIC RIVER A F CREATURES WHO MADE THEM PLUS NEBRASKA COVERED UZZLES ODES BY ANCIENT SWAMPS, EXPLORE P , C , CEANS AND LACIERS AND ACTIVITIES! O , G THE AGES OF THE EARTH REAT AMMALS HO G M W THE STRANGE AND WONDERFUL ALKED THE ARTH W E TOADSTOOLS OF NEBRASKA AND ARE NOW EXTINCT Forest Service FS-1162 January 2021 TOADSTOOL GEOLOGIC PARK, OGLALA NATIONAL GRASSLAND The fascinating landforms of Toadstool Geologic to erosion. When softer, less cemented rock Park hold the secrets of an ancient world where underlies harder, erosion-resistant rock, the strange and wonderful animals walked the Earth. softer rock will be more easily eroded by water Imagine seeing rhinoceroses, miniature horses, and wind, undermining the harder resistant giant tortoises, camels, and a wild pig so huge rock. The harder rock pieces cap the eroded and ferocious that it’s called the “hell pig” in material, forming many unique landforms western Nebraska. These creatures inhabited including toadstools, in what is known as a a landscape unlike the one you see today. Fifty “badlands” landscape. At Toadstool Geologic million years ago, western Nebraska was a Park, sandstone is the harder rock forming the vast, open savannah with streams meandering caps of the toadstools and finer grained silts and through forests. Far to the west, volcanoes clays are the more easily eroded rocks forming erupted and ash drifted east to cover the the pillars. landscape. The secrets of this ancient world are held in the bedrock formations of the Toadstool ACTIVITY: MAKE A TOADSTOOL Geologic Park. As you read this activity book and Get some water and sand or dirt. Moisten the work the puzzles, let your imagination wander to sand a little bit and then pack it into a flat box, this ancient time in our Earth’s history. like a cake pan. Flip it over as though you are making a sand castle. Cover the top of the TOADSTOOLS sand block with flat pebbles and then sprinkle Toadstool is a funny name for a certain type of water over the top. The softer sand will erode landform. You can see these rock toadstools out from beneath the edges of the flat pebbles, capped with flat rocks across the park and creating a toadstool landscape. For a more recognize their resemblance to real toadstools natural approach, try leaving your toadstool or mushrooms. How do they form? Rock model outside during a rain storm and observe layers can be more resistant or less resistant erosion firsthand. Sandstone pieces protect Mimic the process of mak- softer layers underneath, ing toadstool formations while unprotected parts using water, sand, and erode away. small rocks. ERODED BEDROCK LEDGE BADLAND LANDSCAPE TOADSTOOL RESISTANT SANDSTONE BEDROCK FALLEN TOADSTOOL LESS RESISTANT SILTSTONE AND CLAYSTONE BEDROCK 2 THE AGE OF THE EARTH AS A 60-MINUTE (ONE HOUR) IntERVAL Imagine the age of the Earth as the length of The ages of the geologic eras are shown as a favorite television show or the length of your shaded portions. The Toadstool Geologic Park PE (phyical education) class, 60 minutes, as activity book addresses the incredible history illustrated below by the stopwatch. The Earth of the Cenozoic Era, the Age of Mammals, in was formed at the zero-minute mark and the western Nebraska. The Cenozoic Era lasted stopwatch runs to the present at 60 minutes from 65 million years ago to the present. During (one hour). Every minute on the stopwatch the Cenozoic Era in Nebraska, strange looking represents 75 million years (75,000,000 years). mammals walked the Earth and left their tracks. Major events in Earth’s history are illustrated by Many became extinct but some evolved into our the number of minutes it took to arrive there modern North American fauna. Man appeared on starting from the Earth’s formation at time zero. the scene just seconds away from the present. 3 THE PHANEROZOIC EON—”THE TIME OF REVEALED LIFE” The Phanerozoic Eon is represented by the last floor, sand collects on a beach or desert, coal 8 minutes on the 60-minute stopwatch. It is is formed in swamps, and ash and lava are divided into 3 eras which are further divided into ejected from volcanoes. Younger sediments are periods as shown in the table below. We know deposited on top of older rock layers and, if more about the Phanerozoic Eon than any other they are undisturbed, they stay this way. From time in Earth’s history. Why? Geologists have put this and other information, geologists have together the history of the Earth by studying the recreated the history of the Earth. The history rock layers and the fossils in them. Geologists of the area that is now western Nebraska is know that limestone is deposited on an ocean summarized below. ERA PERIOD / EPOCH SYMBOL APPROXIMATE AGE GEOLOGIC EVENTS IN WESTERN NEBRASKA QUATERNARY Q HOLOCENE PRESENT TO 10,000 THE “RECENT”, COMING OF MAN IN N. AMERICA THE ICE AGE, GLACIATION ACROSS THE NORTH PLEISTOCENE 10,000 TO 2 M.Y. AMERICAN CONTINENT, DEPOSITION ON THE PLAINS TERTIARY T VOLCANIC ERUPTIONS TO THE WEST PLIOCENE 2 M.Y. TO 6 M.Y. EXTENSIVE DEPOSITION IN WESTERN NEBRASKA FROM EROSION OF MOUNTAINS TO THE WEST CENOZOIC MIOCENE 6 M.Y. TO 22.5 M.Y. REGIONAL UPLIFT, MOUNTAIN BUILDING TO THE (MEANS NEW LIFE) (MEANS AGE OF MAMMALS OF AGE WEST, DEPOSITION ON THE NEBRASKA PLAINS OLIGOCENE 22.5 M.Y. TO 36 M.Y. VOLCANIC ACTIVITY TO THE WEST, DEPOSITION EOCENE 36 M.Y. TO 58 M.Y. OF ASH ACROSS THE PLAINS EROSION OF OLDER SEDIMENTS PALEOCENE 58 M.Y. TO 65 M.Y. LARAMIDE OROGENY - EPISODE OF MOUNTAIN BUILDING THAT CREATED THE PRESENT DAY STRUCTURE OF THE ROCKY MOUNTAINS CRETACEOUS K 65 M.Y. TO 141 M.Y. COASTAL AND MARINE DEPOSITION FROM A SHALLOW SEA JURASSIC J 141 M.Y. TO 195 M.Y. AGE OF AGE ERODED LAND SURFACE DINOSAURS MESOZOIC TRIASSIC TR 195 M.Y. TO 230 M.Y. MOUNTAIN BUILDING TO THE WEST, ERODED (MEANS MIDDLE LIFE) (MEANS LAND SURFACE TO THE EAST EROSION OF LAND SURFACE TO THE WEST WITH PERMIAN P 230 M.Y. TO 280 M.Y. DRY ARID CONDITIONS IN WESTERN NEBRASKA LIFE PENNSYLVANIAN P 280 M.Y. TO 310 M.Y. SHALLOW SEA, SWAMPS, AND SHORELINE TERRESTRIAL MISSISSIPPIAN M 310 M.Y. TO 345 M.Y. SHALLOW SEA; OUACHITA OROGENY - EPISODE OF MOUNTAIN BUILDING TO THE SOUTH DEVONIAN D 345 M.Y. TO 395 M.Y. LOW ELEVATION LAND THEN SHALLOW SEA FISH PALEOZOIC SILURIAN S 395 M.Y. TO 435 M.Y. LOW LAND SURFACE AND EROSION (MEANS ANCIENT LIFE) (MEANS ORDOVICIAN O 435 M.Y. TO 500 M.Y. MARINE DEPOSITION IN A SHALLOW SEA CAMBRIAN C 500 M.Y. TO 600 M.Y. ERODED LAND SURFACE THEN MARINE DEPOSI- IN THE SEAS IN LIFE EXPLODES EXPLODES LIFE TION PRECAMBRIAN p C 4 THE PEnnSYLVANIAN PERIOD: 300 MILLION YEAR-OLD OCEAN SHORES, MUDFLATS, SWAMPS, AND STREAMS The shoreline of an ancient ocean covered what sometimes formed when the ground surface is now western Nebraska around 300 million was exposed for lengthy times, and the soils years ago. Beaches, tidal basins, and swamps were preserved as colorful red or green-hued developed along the shore. The water level bedrock layers. Trees growing in western of the ocean rose and fell over time, creating Nebraska during the Pennsylvanian Period deposits of sandstone, shale, and limestone. looked very different from modern trees, with Plant matter in the swampy areas became the the appearance of ferns and horsetail rushes as source material for coal deposits. Soil layers shown in the drawings below. Cordaites Lepidodendron Sigillaria Calamites 5 THE PEnnSYLVANIAN PERIOD: 300 MILLION YEAR-OLD OCEAN SHORES, MUDFLATS, SWAMPS, AND STREAMS Animal life was also different in the through the air. Corals, clams, and echinoderms Pennsylvanian Period at the close of the (starfish-like creatures) lived on the ocean Paleozoic. Ancient reptiles and amphibians floor while fish and sharks swam through slithered and crept through the swamps and the open water. shorelines and giant dragonfly-like insects flitted KEY TOADSTOOL GEOLOGIC PARK RIVER SOUTH DAKOTA MARSH NEBRASKA CHADRON ^ LAND SURFACE OGLALA NATIONAL OCEAN GRASSLAND SCOTTSBLUFF NORTH PLATTE WYOMING NEBRASKA COLORADO There are three maps like this throughout the booklet. They these watery ecosystems were not the same during the entire show the different habitats that existed during a certain period period. Over hundreds of thousands of years some marsh would in Nebraska’s geologic history. Note how they change with time. become ocean, and then ocean would become marsh again. How This map shows oceans and marshes covering western Nebraska would the plant and animal life of this time be different than during the Pennsylvanian Period. The specific areas covered by those of today? ACTIVITY: Read the descriptions of animals in the Pennsylvanian Period above. Draw an example of one of those in the space below. You can also add color to any of the drawings in this book. 6 THE CRETACEOUS PERIOD: A 75 MILLION YEAR-OLD SHALLOW SEA IN NEBRASKA Western Nebraska during the Cretaceous Period Mexico and separated North America into several was completely covered by a shallow sea that large land masses. These shallow Cretaceous geologists call the Western Interior Seaway. This oceans teemed with prehistoric marine life while ocean stretched from the Arctic to the Gulf of dinosaurs roamed over the land. The drawing above shows a mosasaur, a large on stalks and are sometimes called sea-lilies.