HGMS Dinosaur Tracks Field Trip

August 6, 2005

STOP 1, "Main" Track Site

Called Site #1 in park literature, this is the most frequently visited track site, located across from the stepping stones on the northwest side of the park. Watch your step as you cross the stepping stones to get to the tracks.

The track bed hear sits a little higher than in most other areas, allowing the prints to be viewed even when most other sites are under water. The park makes an effort to keep this site clean and dry, so that visitors always have some real tracks to see. However, to minimize damage from tourists, the tracks here are usually kept roped off, and visitors may only view them from a distance.

There are two main sections of the main site. The one near the west bank has been exposed since the park opened. Several tracks originally exposed here have become eroded severely or effaced altogether--including one of the best preserved sauropod manus (front foot) prints known, and a curved depression that might have been a tail "swish." However, as the bank erods westward, new tracks are periodically exposed. The variability in depth and clarity of the tracks may be due to differences in the consistency of the sediment where each foot was placed, the partular time that each dinosaur walked (probably no more than days between each trail) and the amount of erosion each marking has sufferred in modern times.

The second area of the main site, which Ron Hastings and I first uncovered in 1986, features several theropod tracks and striding sequence of sauropod tracks. The latter head south, like most sauropod tracks in the park, and probably connects with one of R.T. Bird's trackways farther upstream. Note that most of the sauropod front prints are missing or incomplete as a result of overlap or mud pushed from the rear prints. Also note the narrow gauge of the trail, and the absence of a tail mark. These common track features showed that most early reconstructions of sauropods showing sprawling gaits and dragging tails were incorrect, and that like other dinosaurs, they placed their feet well under the body and usually carried their tails aloft. The most interesting feature on this site is an exception to the rule: a long rut which might be a tail drag. It is straddled by two theropod trails, making it difficult to determine whose tail was dragging. The mark appears to continue into the track area near the west bank. If this is a tail drag, it might represent a sick or wounded animal.

The shelf next to the main site, whose surface is about a meter above the main track bed, is full of erosional undulations and karren solution pits. Many tourists search among the random markings on this surface for tracks, and some strict creationists have claimed a number of "man tracks" here. However, there are no real tracks on the shelf. Finding supposed prints here is like finding faces in clouds. None of the markings on the shelf show distinct and natural print features, or occur in normal striding sequences.