The rocks in the park and adjoining areas were laid down along the margins of an oscillating, but generally advancing shallow sea from about 140 to 100 million years ago.

The deposits from this period are about 250 feet thick. They belong to the Comanchean Series and are divided into three formations:

The lowermost, sandy, Twin Mountains Formation.

The middle, mostly limestone, Glen Rose Formation.

The uppermost, a fine quartz arenite sandstone, Paluxy Formation.

When the sediments for this area were first laid down, this part of Texas was part of a low-lying coastal area. As sea levels rose and fell, the marine and coastal habitats changed. At times the area where the tracks are located was exposed as the beach front. At other times, the area was covered by a shallow sea in which a coral reef was able to form. While you are hiking through the park, take a look at the rocks around you. You may very well be hiking over fossilized coral! A good place to see fossilized coral reef formations is on the Billy Paul Baker Memorial Overlook (Yellow) trail just above track area #2.

In the immediate area of the park, only the Lower Glen Rose Formation contains dinosaur tracks. Sometimes potholes in the ground can be deceiving mimics of tracks, but if you look for the correct rock layer, you'll be able to tell what is real. Tracks have been found in the other two formations elsewhere in the state.

As the sea levels fell and the region changed, the area became more recognizable as it is now. What was once a coastline much like modern day Galveston or Corpus Christi is now the rolling hills, limestone cliffs, and scrub land that you see today.