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Dinosaur Ridge

    Stretching north from Morrison to just south of Golden, Dinosaur Ridge became famous for the dinosaur fossils and tracks discovered there in 1877. The discoveries, which included the world’s first known Stegosaurus and Apatosaurus fossils, helped launch a “dinosaur rush” in the late nineteenth century. New fossils and tracks continue to be found on the ridge, which is protected by county, state, and federal designations.

    Geology

    The rock layers that make up Dinosaur Ridge contain many millions of years of history. During the Jurassic period, about 145 million to 201 million years ago, the area that is now Colorado consisted of a low plain crossed by slow-moving rivers. Dinosaurs lived and died along the rivers. Sometimes their bones were fossilized in the river mud and sand. Rock layers from this period are now known as the Morrison Formation.

    Later, during the Cretaceous period, eastern Colorado was submerged under an inland sea from about 110 million to 70 million years ago. What is now the Front Range served for a time as a “freeway” for dinosaurs migrating along the western edge of the inland sea. The rocks from this period are now called the Dakota Group. As sea levels continued to rise, much of Colorado was eventually under water.

    About 65 million years ago the sea drained, and a sudden uplift called the Laramide orogeny formed huge mountains where the Rockies are today. This activity tilted the old inland seabed at up to a 45-degree angle. Around 40 million years ago, however, the mountains began to quickly erode. A volcanic period known as the Ignimbrite Flare-Up buried them under ash.

    As a result of the flare-up and further erosion, the area we know as the Front Range was essentially a continuation of the Great Plains as recently as 5 million years ago. At that point a period of intense erosion began, washing away softer rock layers to reveal the much older and harder rocks that make up the Rocky Mountains. The old tilted seabed layers came to the surface as a long chain of ridges, or hogbacks, at the edge of the foothills. Dinosaur Ridge is one of those hogbacks.

    Early Fossil Discoveries

    Arthur Lakes (1844–1917) discovered the first known fossils on Dinosaur Ridge in 1877. Originally from England, Lakes attended Oxford University before immigrating to the United States in the 1860s. He had arrived in Colorado Territory by 1867. He became a geology instructor at Jarvis Hall in Golden, which developed into the Colorado School of Mines in the 1870s, and he also served as an Episcopal minister, preaching in nearby mining towns.

    On March 20, 1877, Lakes and Henry C. Beckwith, a retired naval officer, were exploring the west side of the hogback just north of Morrison when they came across some large fossilized bones. Lakes recognized them as similar to dinosaur fossils he had seen in England. He sketched the bones and sent his drawings, along with a description of the find, to the paleontologist Othniel Charles Marsh at Yale University. “A few days ago,” he wrote, “I discovered . . . some enormous bones apparently a vertebra and a humerus bone of some gigantic saurian in the Upper Jurassic or Lower Cretaceous at the base of Hayden’s Cretaceous No. 1 Dakotah group.”

    Lakes continued to explore the area. In late April he sent a second letter to Marsh, saying he had found a huge femur indicating an animal about sixty feet long. Marsh, one of the most famous paleontologists in America, did not respond. Nevertheless, in May Lakes shipped Marsh about 2,000 pounds of bones and rocks he had excavated from his quarry near Morrison. Lakes also sent a letter and some bones to Marsh’s main competitor, Edward Drinker Cope, with whom Marsh had a bitter rivalry.

    The possibility of losing the find to his rival finally got Marsh’s attention. Marsh quickly wrote a “Notice of a New and Gigantic Dinosaur” for the July issue of the American Journal of Science, in which he said the new dinosaur “surpassed in magnitude any land animal hitherto discovered.” He hired Lakes as a bone collector and dispatched one of his lead collectors, Benjamin Franklin Mudge, to work with Lakes at the Morrison site. By the middle of July the pair had another 2,500 pounds of rocks and bones ready to ship. Along with a nearly simultaneous discovery of big bones at Como Bluff, Wyoming, the excavations at Dinosaur Ridge marked the start of what has been called the “dinosaur rush” in America.

    Lakes continued to collect bones for Marsh on Dinosaur Ridge until 1879, when he closed his quarries. The new dinosaur genera discovered at Dinosaur Ridge during these years included Allosaurus, Apatosaurus, Diplodocus, and Stegosaurus, the latter of which is now the state fossil of Colorado. In addition, the rock layer in which Lakes made his discoveries was named the Morrison Formation after the town of Morrison.

    Dinosaur Track Discoveries: Alameda Parkway, 1937

    Alameda Parkway was extended over Dinosaur Ridge to Red Rocks when the Red Rocks Amphitheatre was under construction in the late 1930s. Construction exposed rock layers that had previously been hidden or difficult to access. In 1937 workers discovered dinosaur tracks in rock layers from the Dakota Group on the east side of the ridge. New excavations and maps of the tracks in 1992–93 revealed a total of 335 tracks and 37 trackways. Ten different rock strata contain tracks, with at least 78 individual dinosaurs represented in tracks preserved on the ridge.

    The tracks found in the Dakota Group originated 50 million years later than the fossils found in the Morrison Formation. As a result, they represent different dinosaurs. There were few known fossilized bones from this period until recently, so the tracks, which provide evidence about movement and behavior, have played a large role in the way paleontologists understand these dinosaurs.

    The tracks on Dinosaur Ridge primarily record the activity of Iguanadon-like herbivores and ostrich-sized carnivores. The herbivores walked on all fours at about two miles per hour, and evidence of parallel tracks indicates that they traveled in groups. The carnivore tracks, which are about nine inches long, reveal animals that weighed 100 pounds and walked upright on two legs at a speed of five miles per hour. They traveled alone. All these tracks were made about 100 million years ago, when the dinosaurs were migrating north and south on the “Dinosaur Freeway” along the shore of the ancient inland sea.

    Recent History

    The nonprofit Friends of Dinosaur Ridge was formed in 1989 to help preserve the site and educate visitors. The group operates a visitor center on the east side of the ridge as well as a newer Discovery Center, which opened in 2014, on the west side of the ridge. The group also maintains West Alameda Parkway over the ridge, which is now closed to vehicle traffic, and has erected a series of interpretive signs to help visitors understand the ridge’s many tracks, bones, and geological features. On the west side of the ridge, Alameda Parkway passes near one of Lakes’s original bone quarries—Quarry #5. In 1995 Friends of Dinosaur Ridge constructed a pedestrian ramp that enables visitors to see the fossils still entombed in rock at the quarry site.

    Lakes’s original quarries on Dinosaur Ridge were closed in 1879, his last year of hunting for fossils on the ridge, and they remained largely dormant for more than 120 years. In the early twenty-first century, researchers at the Morrison Natural History Museum rediscovered one of the quarries and began to examine it again. In 2003 they found the first Stegosaurus footprints ever discovered in Colorado, and in 2006 they made the first discovery in the world of baby Stegosaurus tracks. In early 2016, University of Colorado–Denver geologist Martin Lockley found two-toed raptor tracks on Dinosaur Ridge. The 105-million-year-old tracks were the first two-toed tracks discovered in Colorado and the second ever found in North America.

    Dinosaur Ridge has been recognized multiple times at the federal and state levels as a site with significant historical and scientific value. It has been designated by the National Park Service as a National Natural Landmark (1973), by the state of Colorado as a State Natural Area (2001), and by the Colorado Geological Survey as a Point of Geological Interest (2006). In addition, much of the ridge lies within Jefferson County’s Open Space system.

    Dinosaur Ridge is a hogback located near the town of Morrison that is famous for the dinosaur fossils and tracks discovered there. The discoveries include the world’s first known Stegosaurus and Apatosaurus fossils. New fossils and tracks continue to be found on the ridge.

    Geology

    The rock layers that make up Dinosaur Ridge contain millions of years of history. During the Jurassic period (about 145–201 million years ago) the area that is now Colorado was a low plain crossed by slow-moving rivers. Dinosaurs lived and died along the rivers. Sometimes their bones were fossilized in the river mud and sand. Rock layers from this period are now known as the Morrison Formation.

    Later, during the Cretaceous period (about 110–70 million years ago) eastern Colorado was submerged under an inland sea. What is now the Front Range served a migration route along the western edge of the sea. The rocks from this period are called the Dakota Group. As sea levels continued to rise, much of Colorado was covered with water.

    About 65 million years ago the sea drained. A sudden uplift called the Laramide orogeny formed huge mountains where the Rockies are today. This activity tilted the old inland seabed up at a 45-degree angle. Then, around 40 million years ago, the mountains began to erode. A volcanic period known as the Ignimbrite Flare-Up buried the mountains under ash.

    Five million years ago, the area we know as the Front Range was a continuation of the Great Plains. At that point, a period of intense erosion began. Ash and softer rock layers wore away. The older and harder rocks that make up the Rocky Mountains were uncovered. The tilted seabed layers came to the surface. They formed a long chain of ridges or hogbacks along the edge of the foothills. Dinosaur Ridge is one of those hogbacks.

    Early Fossil Discoveries

    Arthur Lakes (1844–1917) discovered the first known fossils on Dinosaur Ridge in 1877. Originally from England, Lakes attended Oxford University before immigrating to the United States in the 1860s. He arrived in Colorado Territory by 1867. He became a geology instructor at Jarvis Hall in Golden. That school became the Colorado School of Mines in the 1870s. He also served as an Episcopal minister, preaching in nearby mining towns.

    On March 20, 1877, Lakes and Henry C. Beckwith, a retired naval officer, were exploring the west side of the hogback. They came across some large fossilized bones. Lakes recognized them as similar to dinosaur fossils he had seen in England. He sketched the bones and sent his drawings and a description to paleontologist Othniel Charles Marsh at Yale University. Marsh was one of the most famous paleontologists in America, telling him that he had found “some enormous bones … at the base of Hayden’s Cretaceous No. 1 Dakota group.” He did not hear back from Marsh.

    Lakes continued to explore the area. In April he sent a second letter to Marsh, saying he had found a huge femur indicating an animal about sixty feet long. Again, Marsh did not respond. Nevertheless, Lakes shipped Marsh about 2,000 pounds of bones and rocks he had excavated from the site. Lakes also sent a letter and some bones to Marsh’s main competitor, Edward Drinker Cope. Marsh and Cope had a bitter rivalry.

    The possibility of losing the find to his rival finally got Marsh’s attention. Marsh wrote a “Notice of a New and Gigantic Dinosaur” for the July issue of the American Journal of Science. He said the new dinosaur “surpassed in magnitude any land animal hitherto discovered.” He hired Lakes as a bone collector and sent one of his collectors, Benjamin Franklin Mudge, to work with Lakes. By the middle of July the pair had another 2,500 pounds of rocks and bones ready to ship. There had been a similar discovery of big bones at Como Bluff, Wyoming. These finds started what has been called the “dinosaur rush” in America.

    Lakes continued to collect bones for Marsh on Dinosaur Ridge until 1879. The new dinosaurs discovered at Dinosaur Ridge during these years include Allosaurus, Apatosaurus, Diplodocus, and Stegosaurus. The Stegosaurus was named the state fossil of Colorado.

    Dinosaur Track Discoveries

    When Red Rocks Amphitheatre was built in the l930s, Alameda Parkway was extended over Dinosaur Ridge. The construction exposed rock layers that had been hidden or difficult to access. In 1937 workers discovered dinosaur tracks from the Dakota Group on the east side of the ridge. Excavations and maps of the tracks show a total of 335 tracks and 37 trackways. Ten different rock strata contain tracks, with at least seventy-eight individual dinosaurs making the tracks preserved on the ridge.

    The tracks found in the Dakota Group were made 50 million years later than the fossils found in the Morrison Formation. The bones and the tracks were from dinosaurs of different geologic periods. There were few known fossilized bones from this period. The tracks provided information about dinosaur movement and behavior. The discovery played a large role in the way paleontologists understand these dinosaurs.

    The tracks on Dinosaur Ridge show the movement of Iguanadon-like herbivores and ostrich-sized carnivores. The herbivores walked on all fours at about two miles per hour. Evidence of parallel tracks indicates that they traveled in groups. The carnivore tracks, which are about nine inches long, reveal animals that weighed 100 pounds. They walked upright on two legs at a speed of five miles per hour. They traveled alone. All these tracks were made about 100 million years ago, when the dinosaurs were migrating on the “Dinosaur Freeway” along the shore of the ancient inland sea.

    Recent History

    The nonprofit Friends of Dinosaur Ridge was formed in 1989 to help preserve the site and educate visitors. The group operates a visitor center and a Discovery Center. The group maintains West Alameda Parkway over the ridge, which is now closed to vehicle traffic. They have put up a series of interpretive signs to help visitors understand the ridge’s many tracks, bones, and geological features. On the west side of the ridge, Alameda Parkway passes near one of Lakes’ original bone quarries—Quarry #5. In 1995 Friends of Dinosaur Ridge built a pedestrian ramp that enables visitors to see the fossils still entombed in rock at the quarry site.

    Lakes’ original quarries on Dinosaur Ridge were closed in 1879, his last year of hunting for fossils on the ridge. They remained dormant for more than 120 years. In the early 2000s, researchers at the Morrison Natural History Museum rediscovered one of the quarries. They began to examine it again. In 2003 they found the first Stegosaurus footprints ever discovered in Colorado. In 2006 they made the first discovery in the world of baby Stegosaurus tracks. In early 2016, University of Colorado–Denver geologist Martin Lockley found two-toed raptor tracks on Dinosaur Ridge. The 105-million-year-old tracks were the first two-toed tracks discovered in Colorado and the second ever found in North America.

    Dinosaur Ridge has been recognized at the federal and state levels as a site with significant historical and scientific value. It has been designated by the National Park Service as a National Natural Landmark (1973), by the state of Colorado as a State Natural Area (2001), and by the Colorado Geological Survey as a Point of Geological Interest (2006). In addition, much of the ridge lies within Jefferson County’s Open Space system.

    Located on a hogback near the town of Morrison, Dinosaur Ridge is famous for the discovery of dinosaur fossils and tracks. The findings include the world’s first known Stegosaurus and Apatosaurus fossils. New fossils and tracks continue to be found on the ridge.

    Geology

    The rock layers that make up Dinosaur Ridge contain millions of years of history. During the Jurassic period (145–201 million years ago) the area was a low plain crossed by rivers. Dinosaurs lived and died along the rivers. Sometimes their bones were fossilized in the river mud and sand. Rock layers from this period are now known as the Morrison Formation.

    Later, during the Cretaceous period (110–70 million years ago) Colorado was covered by an inland sea. Dinosaurs moved along the edge of the sea. The rocks from this period are now called the Dakota Group. As sea levels continued to rise, much of Colorado was under water.

    About 65 million years ago the sea drained. A sudden uplift called the Laramide orogeny formed huge mountains where the Rockies are today. This activity tilted the old inland seabed up to a 45-degree angle. Then, around 40 million years ago, the mountains began to erode. A volcanic period known as the Ignimbrite Flare-Up buried the mountains under ash.

    Five million years ago, the area looked like part of the Great Plains. Then, a period of erosion began. The ash and softer rock layers wore away. The older and harder rocks that make up the Rocky Mountains were uncovered. The old tilted seabed layers came to the surface. They formed a long chain of ridges along the edge of the foothills. The ridges are called “hogbacks.” Dinosaur Ridge is one of those hogbacks.

    Early Fossil Discoveries

    Arthur Lakes discovered the first known fossils on Dinosaur Ridge in 1877. He was from England and attended Oxford University. He immigrated to the United States in the 1860s. Colorado School of Mines hired him as a geology teacher. He also served as an Episcopal minister, preaching in nearby mining towns.

    In March 1877, Lakes and Henry C. Beckwith were exploring the west side of the hogback. They came across some large fossilized bones. They reminded Lakes of dinosaur fossils he had seen in England. He sketched the bones. He sent his drawings and a description to paleontologist Othniel Charles Marsh at Yale University. Marsh was one of the most famous paleontologists in America. Lakes did not hear back from Marsh.

    Lakes continued to explore the area. In late April he sent a second letter to Marsh, saying he had found a huge leg bone. He believed the animal had been about sixty feet long. Again, Marsh did not respond to his letter. So Lakes shipped him bones and rocks he had excavated from the site. But this time, Lakes also sent a letter and some bones to Marsh’s main competitor, Edward Drinker Cope. Marsh and Cope were competing to be America’s most noted paleontologist.

    The possibility of losing the find to his rival finally got Marsh’s attention. Marsh published an article titled “Notice of a New and Gigantic Dinosaur” for the American Journal of Science. He wrote that the new dinosaur was the biggest ever discovered. He hired Lakes as a bone collector. By the middle of July, Lakes had 2,500 pounds of rocks and bones ready to ship. There had also been another discovery of big bones at Como Bluff, Wyoming. These finds started the “dinosaur rush” in America.

    Lakes continued to collect bones for Marsh on Dinosaur Ridge until 1879. New species of dinosaurs were discovered at Dinosaur Ridge, including Allosaurus, Apatosaurus, Diplodocus, and Stegosaurus. The Stegosaurus was later named the state fossil of Colorado.

    Dinosaur Track Discoveries

    Red Rocks Amphitheater was built in the 1930s. The construction of a road to Red Rocks exposed rock layers that had been hidden. In 1937 workers discovered dinosaur tracks from the Dakota Group on the ridge. By 1993 they had mapped 335 tracks. The tracks of at least seventy-eight individual dinosaurs are preserved on the ridge. The tracks provide information about dinosaur movement and behavior.

    The tracks on Dinosaur Ridge are from Iguanadon-like herbivores and ostrich-sized carnivores. The herbivores walked on four legs at about two miles per hour and traveled in groups. The carnivore tracks show that the animals weighed 100 pounds. They walked upright on two legs at a speed of five miles per hour and traveled alone. The dinosaurs were migrating on the “Dinosaur Freeway” along the shore of the ancient sea.

    Recent History

    The nonprofit Friends of Dinosaur Ridge was formed in 1989. The group helps preserve the site and educate visitors. It operates a visitor center and a discovery center. The road over the hogback is now closed to cars. Visitors can walk along paths and see the tracks and bones. Interpretive signs help visitors understand the ridge’s many tracks, bones, and geological features. Visitors can also see one of Lakes’s original bone quarries.

    Lakes’ original quarries on Dinosaur Ridge were closed in 1879. No one explored them for more than 120 years. In the early twenty-first century, researchers rediscovered the quarries and began to examine them again. In 2003 they found the first Stegosaurus footprints ever discovered in Colorado. Later, they discovered baby Stegosaurus tracks. They also found two-toed raptor tracks on Dinosaur Ridge. The 105-million-year-old tracks were the first two-toed tracks discovered in Colorado.

    Dinosaur Ridge has been recognized as a site with significant historical and scientific value. It has been designated by the National Park Service as a National Natural Landmark (1973). The state of Colorado named it as a State Natural Area (2001). The Colorado Geological Survey calls it a Point of Geological Interest (2006).

    Dinosaur Ridge is a place where many dinosaur fossils and tracks were discovered. The world’s first known Stegosaurus and Apatosaurus fossils were found at the site. New fossils and tracks continue to be found on the ridge. It is located near Red Rocks Amphitheater and the town of Morrison.

    Geology

    Dinosaur Ridge contains millions of years of history. The Jurassic period was 145 to 201 million years ago. Then, the area was a plain crossed by rivers. Dinosaurs lived and died along the rivers. Some of their bones were fossilized in the mud and sand.

    Later came the Cretaceous period. It was 110 million to 70 million years ago. Colorado was covered by an inland sea. Dinosaurs moved along the edge of the sea. Sea levels continued to rise. Much of Colorado was under water.

    About 65 million years ago, the sea drained. An uplift formed huge mountains where the Rockies are today. The old inland seabed tilted up to a 45-degree angle. Volcanoes buried the mountains under ash.

    Then, around 40 million years ago, the mountains began to erode. The ash and soft rock layers wore away. The older rocks that make up the Rocky Mountains were uncovered. The old tilted seabed came to the surface. It became the ridges along the edge of the foothills. The ridges are called “hogbacks.” Dinosaur Ridge is one of those hogbacks.

    Early Fossil Discoveries

    Arthur Lakes discovered the first fossils on Dinosaur Ridge. He was from England. He immigrated to the United States in the 1860s. The Colorado School of Mines hired him as a geology teacher. He also worked as a minister, preaching in mining towns.

    In 1877 Lakes was exploring the hogback. He came across some large fossilized bones. They reminded him of dinosaur fossils he had seen in England. He sketched what he saw. He sent his drawings to Othniel Charles Marsh at Yale University. Marsh was one of the most famous paleontologists in America. Lakes did not hear back from Marsh.

    Lakes continued to explore the area. In late April he sent a second letter to Marsh. He told him he had found a huge leg bone. He said he believed the animal had been enormous. Again, Marsh did not respond to the letter. So Lakes sent him some bones and rocks. But this time, Lakes also sent a letter and some bones to Edward Drinker Cope. Cope wanted to be a more famous paleontologist than Marsh.

    This finally got Marsh’s attention. Marsh wrote an article about the gigantic dinosaur for the American Journal of Science. He said the new dinosaur was the biggest ever discovered. He hired Lakes as a bone collector. Soon 2,500 pounds of rocks and bones were sent to Marsh. There was another discovery of dinosaur bones in Wyoming. These finds started what has been called the “dinosaur rush” in America.

    Lakes continued to collect bones on Dinosaur Ridge until 1879. New species of dinosaurs were discovered at Dinosaur Ridge. They include Allosaurus, Apatosaurus, Diplodocus, and Stegosaurus. The Stegosaurus was later named the state fossil of Colorado.

    Dinosaur Track Discoveries

    Red Rocks Amphitheater was built in the 1930s. A new road to Red Rocks uncovered more rock layers. Workers discovered dinosaur tracks. By 1993, 335 tracks had been uncovered.

    The tracks and the bones were from different time periods. The tracks provided information about dinosaur movement and behavior. The discovery helped paleontologists understand dinosaurs better.

    The tracks on Dinosaur Ridge were made by Iguanadon-like herbivores and ostrich-sized carnivores. The herbivores walked on four legs at about two miles per hour. They traveled in groups. The carnivore tracks show that they weighed 100 pounds. They walked on two legs. They could move five miles per hour and traveled alone. These dinosaurs were migrating along the shore of the ancient sea. The tracks were made about 100 million years ago.

    Recent History

    The group Friends of Dinosaur Ridge was formed in 1989. It helps preserve the site and educate visitors. The group operates a visitor center and a Discovery Center. The road over the hogback is now closed to cars. Visitors can walk along paths and see the tracks and bones. There are signs that help visitors understand the area. Visitors can see one of Lakes’ original bone pits.

    Lakes’ digging sites on Dinosaur Ridge were closed in 1879. No one explored them for more than 120 years. In the 2000s, one of his old pits was investigated. Scientists found Stegosaurus footprints. Later, they discovered baby Stegosaurus tracks. They also found two-toed raptor tracks. These were the first two-toed tracks discovered in Colorado.

    Dinosaur Ridge is a site of historical and scientific value. The National Park Service named it a National Natural Landmark. The state of Colorado calls it a State Natural Area. The Colorado Geological Survey has made it a Point of Geological Interest.