Eagle Sandstone facts for kids
Quick facts for kids Eagle SandstoneStratigraphic range: Late Cretaceous |
|
|---|---|
| Type | Geological formation |
| Underlies | Claggett Shale, Judith River Formation |
| Overlies | Telegraph Creek Formation, Niobrara Shale |
| Thickness | 100 to 350 feet |
| Lithology | |
| Primary | Sandstone |
| Other | Sandy shale |
| Location | |
| Region | Montana |
The Eagle Sandstone is a special type of rock layer found in Montana, USA. These layers of rock formed a very long time ago, during the Late Cretaceous period. This was about 100 to 66 million years ago, when dinosaurs roamed the Earth!
The Eagle Sandstone is mostly made of sandstone, which is rock formed from sand. It can be light gray, brownish gray, or even pale yellow-orange.
What is the Eagle Sandstone Made Of?
This rock formation is mainly sandstone with very fine grains. You might also find areas with crossbedding. This means the layers of sand were deposited at an angle, often by wind or water currents.
Sometimes, there are also layers of sandy shale. Shale is a soft rock made from mud or clay. The Eagle Sandstone also has large, round, sandy lumps called concretions. These can be up to 15 feet wide and are held together by a natural "glue" called calcareous material, which is like the stuff in seashells.
The thickness of the Eagle Sandstone changes a lot, from about 100 to 350 feet. This is because the individual sandstone layers are like lenses, getting thicker and thinner in different places.
Ancient Life and Amazing Shapes
Scientists have found Dinosaur fossils in the Eagle Sandstone! For example, parts of a dinosaur called "Ornithomimus" grandis (which means "bird mimic") have been discovered here. This shows us that dinosaurs lived in this area when the sand was first laid down.
Over millions of years, Weathering (like rain and wind) and erosion (carrying away rock) have shaped the Eagle Sandstone. These natural forces have created some really cool landforms. You can see natural arches, which are like stone bridges, and hoodoos. Hoodoos are tall, thin spires of rock that look like giant totems.
These amazing features can be seen in places like the Upper Missouri River Breaks National Monument in Montana. It's a great place to see how geology shapes our world!
