Introduction
The Garden Park Fossil Area is an Area of Critical Environmental Concern managed by the Bureau of Land Management (BLM). As with all BLM lands it is illegal to collect any vertebrate fossil material without a proper permit and as with all EarthCaches, please adhere to the principles of Leave No Trace. If you do find any fossils on public lands, please take a picture, record its location, and report it to the proper BLM, US Forest Service, or National Park Service office.
Garden Park Fossil Area is one of the most productive and historically important locations in the United States for the study of Late Jurassic dinosaurs. Fossil hunters and scientists from across the country have dug in Garden Park since 1877, when the nearby town of Cañon City, Colorado was still young. Important discoveries include the first complete skeleton of Ceratosaurus, some of the most complete Stegosaurus skeletons, as well as the first known remains of dinosaurs like Camarasaurus, Allosaurus, and Diplodocus.
In addition to dinosaurs, Garden Park has also produced fossils of Late Jurassic mammals, turtles and crocodiles, and a variety of Late Jurassic flora. Fossils from Garden Park are housed in museums as far as New York City and Washington, D.C., and excavations by institutions such as the Denver Museum of Nature and Science continue to this day. Since 1937, the area has been managed by the Bureau of Land Management (BLM) and was added to the National Natural Landmark (NNL) registry by the National Park Service (NPS) in 1972. More recently, the BLM, identified the site as a Research Natural Area in 1991, and in 1996 the site was upgraded to an Area of Critical Environmental Concern (ACEC).
The quarries in Cañon City played an important role in the "Great Dinosaur Rush" of the West and established dinosaurs in the public consciousness. The fossil discoveries in Garden Park affected the whole course of American paleontology and the fossils continue to yield significant scientific and educational information regarding the history of life on earth.
There is a trail that connects all four stops, approximately half of a mile long (one way, starting across the street from Stop 1 and continuing North), or you may drive and park at the first two stops and take the trail for a quarter of a mile to access the last two stops.
For more information regarding the Garden Park Fossil Area, check out http://www.handsontheland.org/garden-park/
Or visit The Royal Gorge Regional Museum and History Center’s display on the fossils of Fremont County. http://rgmhc.org/
Stop 1: Cleveland Delfs Site (38.532889˚, -105.219141˚)
Here you will see plaques and interpretive signs describing The Garden Park Fossil Area and the Morrison Formation. However, one of the plaques is about a different Western explorer who passed through this area 70 years before the discovery of Garden Park’s fossils. What was the name of this U.S. Army Lieutenant?
The site you are standing near was excavated in 1954 by Edwin Delfs, an undergraduate student from Yale, and a group of high school students. Due to their inexperience, some of the techniques used were extremely dangerous to themselves and the fossils but they were able successfully extract a Haplocanthosaurus, a nearly 50 foot long sauropod, which is currently on display at the Cleveland Museum of Natural History.
This quarry is one of many in the Garden Park Fossil Area which showcases the high quantity and quality of fossil preservation in the Morrison Formation. The colorful mudstones formed by floodplains and channels of sandstone formed by rivers depict a warm wet environment where many deceased animals would be quickly buried and preserved by the muds before decaying or being scavenged. One of the informative signs at this site mentions the average thickness of the Morrison and the amount of time the formation covers. Calculate the average sedimentation rate in terms of inches per year for the Morrison formation using the numbers provided. To accomplish this divide the thickness (in inches) by the number of years. This should give you a very small number that represents how many inches of sediment were deposited each year. To put this into context, take 1 and divide it by the number you calculated to see how many years are preserved in just 1 inch of the rock you see in front of you. Had this rate continued until today, there would be over 4,500 feet of rock between your feet and the fossils found here! What forces have changed the landscape and have allowed the fossil bearing rocks to become exposed today? Do you see any evidence of these forces around the site today?
Stop 2: Marsh-Felch Parking Area (38.535023˚, -105.221660˚)
Here you can park at the trail head for the short, quarter of a mile, trail leading to the Marsh Felch Quarry overlooks. There is a plaque that was placed by the State Historical Society of Colorado which features five types of dinosaurs. Four of them have been found within the Garden Park Fossil Area while one of them is not found in the Morrison Formation at all because it did not exist during the Jurassic Period. List all five and guess which one of them does not seem to belong.
Stop 3: Marsh-Felch Lower Overlook (38.536681˚, -105.222956˚)
On your way to the third stop there are more signs about discoveries that have been made in the area both young and old. A modern plant found near the trail only grows on the Morrison and the Dry Union Formations in Fremont and Chaffee Counties of Colorado. What is the name of this rare plant? Were you able to see any from the trail? During the Jurassic Period, the plant life was very different. Flowering plants and most broad-leaved trees had not yet evolved! The ground would have been mostly covered in ferns and mosses, while forests would be dominated by trees similar to Tony’s Tree. What type of tree do you think Tony’s Tree was? (Hint: You can go to the Royal Gorge Regional Museum and History Center to see it for yourself and find out!) When you reach the coordinates you are greeted with a view of the oldest and most productive dinosaur quarry in Garden Park. Look closely at the quarry map on the sign. A theropod dinosaur (two-legged meat-eater similar to T. Rex) named Ceratosaurus was found fully articulated; the bones were still in the same position as when the dinosaur was alive. What year was this Ceratosaurus excavated?
Stop 4: Marsh-Felch Upper Overlook (38.537343˚, -105.223733˚)
The trail continues up the hill to your west leading to your final stop, the upper overlook. You are now at about the same level as the original quarry across the canyon. If you look above the cliff’s edge closely, you will see hard sandstone layers sticking out of the softer red mudstones that make the Morrison Formation famous. Sandstones are generally formed by beaches and streams where the water moves enough to break rock down into sand grains but not moving so much that large pebbles and boulders are deposited. Mudstones generally form in water with very low energy, allowing small particles to settle to the bottom. Floodplains are good places for mudstones to be deposited. On the canyon wall opposite of you there is a large bulge in a thick sandstone layer. According to the signs at this site, what caused this feature? What makes this feature an important clue for paleontologists? Describe what the environment was like here during the Jurassic Period. Was the river a slow, wide, meandering stream, or a quick, narrow mountain stream?
To log this cache: Message or E-mail your answers to all of the questions in bold (listed below) to the owner of this cache or rgfogeologyintern@gmail.com. Do not post answers on the log. Once you have submitted your answers, feel free to log the cache as found. The owner will attempt to reply with the correct answers but may not be able to respond to every submission. You do not need to wait for confirmation from the owner, but any logs without answers submitted, or any logs where it is clear you did not visit the site, may be removed.
1. What was the name of this U.S. Army Lieutenant?
2. Calculate the average sedimentation rate in terms of inches per year for the Morrison formation using the numbers provided.
3. How many years are preserved in just 1 inch of the rock?
4. What forces have changed the landscape and have allowed the fossil bearing rocks to become exposed today?
5. Do you see any evidence of these forces around the site today?
6. List all five and guess which one of them does not seem to belong.
7. What is the name of this rare plant?
8. Were you able to see any from the trail?
9. What type of tree do you think Tony’s Tree was?
10. What year was this Ceratosaurus excavated?
11. What caused this feature?
12. What makes this feature an important clue for paleontologists?
13. Describe what the environment was like here during the Jurassic Period.
Optional: Post a photo of you, your group, or your device with the Marsh-Felch Quarry in the background.
This EarthCache was produced by a collaboration between the Bureau of Land Management (BLM) Royal Gorge Field Office and the Geocorps America program of the Geological Society of America.
