Animation. A three-toed dinosaur foot with sharp claws makes an impression in sand.

Sam: Most traces of life get washed away before they can become fossils. However, in the right conditions, these traces can be buried by sediments.

Water washes over the footprint. Layers of sand and soil fill in the footprint and continue to bury it deeper and deeper below the surface. As the camera zooms out more and more layers of sediment bury the footprint.

Sam: If enough sediment piles up over time, heat, pressure and chemical changes solidify the sediment and turn it into rock. This process is called lithification. These changes happen deep beneath the Earth's surface, where most of these rocks will remain buried.

The rocks layers start to move and bend. They are being uplifted to form a mountain.

Sam: Under the right tectonic conditions uplift can bring the rocks to the surface.

Erosion starts to wear away the rock layers from the top down. Eventually the fossilized footprint buried far below is exposed on the surface.

Sam: Once on the surface, erosion from wind, rain, and ice breaks down the rock layers on top. This exposes the rock layers underneath and sometimes exposes trace fossils. Hi, my name is Sam Shekut. I'm a PhD candidate here at the University of British Columbia, where I study sedimentary geology.