Paleontology: Dinosaur Footprints in Leander, Texas

In Leander, Texas, along the stream bed of the South Fork of the San Gabriel River, dinosaur (extinct reptile) footprints are evident in the exposed limestone.  This location is west of the US183 and San Gabriel River intersection right at the first bend in the stream valley.

The geology consists of inter-bedded limestone rock, marly (clayey) limestone, sandy clay-marl, weak limestone material, and nodular limestone sedimentary deposits categorized as the "Walnut Group" geologic formation that includes "Cedar Park Limestone", "Bee Cave Marl", and "Bull Creek Marl" members.  The layers of marl and weak limestone materials are erodible, so the currently exposed dinosaur footprints are in a limestone rock layer (resistant).  The stream valley walls show evidence of inter-bedding as the overlying layers have eroded while the currently exposed rock layers have remained more resistant to stream flood water erosion and weathering.

The photo shows the largest tracks, assumed to be from a theropod or ornithopod type dinosaur.  There are some other smaller tracks scattered around also from 3-toed (tridactal) dinosaurs.  This geologic formation was either deposited during the ascending phase of one creationist geologic model when footprints would have been made in soft (yielding) soil and quickly buried and preserved by the next event of sedimentation, or during the Cretaceous age of the uniformitarian model of millions of years, depending on which paradigm someone is working under. If working under the creationist model this strata was likely buried under subsequent sediment layers but then subsequently exposed after the abative geologic phase eroded off alot of the overlying strata and river floods finished off the rest to expose the site in its current condition.