Studying Footprints of a Trackway

Eldon George collected more than two hundred samples of ancient fossil footprints and trackways along the Parrsboro Shore.

  • For nearly sixty years Eldon gathered fossil footprints from over a dozen locations along the along the shore of the Minas Basin, Bay of Fundy.
  • Most of the footprints are from animals that lived in the Carboniferous – over 300 million years ago, but Eldon also collected several important dinosaur footprints.

Looking at fossil footprints and other ‘trace fossils’ requires careful and detailed observation. Palaeontologists and geologists examine the fine details of sedimentary rocks to identify clues for interpreting the ancient evidence.

Below is an photograph of a specimen that Eldon George discovered with his son Kevin in 1990 when they were walking the beach near Fox River, Nova Scotia.  The scale bar shows the sandstone slab is about 25 cm long and 20 cm wide.

Fossil Footprints from Fox River, Nova Scotia
Specimen found by Eldon and Kevin George in 1990.

Studying fossil footprints starts with identifying the significant marks and features by creating an outline drawing. Below is a photo that shows three footprints with clearly recognized toes, and two areas (dashed lines) where the footprints are not as clear.

Fossil footprints outlined
Fossil footprints outlined with drawing.

The footprints represent the traces left in the soft sediment as the animal walked on a soft muddy surface. The soft mud oozed and flowed around the toes as the animals weight pressed down into the wet ground. Sand quickly covered the surface and filled in the footprints. The shape of the footprints made by the same foot can look quite different depending on if the ground is soft or firm.

Fossil footprints shaded
Outlines shaded to show three footprints and two unclear depressions.

Of the three preserved footprints, there is one that is larger than the other two. Based on experience with other specimens, the larger footprint is considered the pes, or back foot. The two smaller footprints are made by the manus, or front foot.

When counting the number of toes preserved in the footprints, it is important to remember each footprint might only preserve some of the digits. Partial preservation and other variations in shape of footprints are what ichnology (study of trace fossils, footprints) challenging.

  • The two manus prints appear to have five digits, the three middle digits being similar in length, with the smaller first and fifth digits directed in opposite directions (180º).
  • The pes print has five digits (toes), the three inner digits being similarly long.
  • The fossil is a natural cast of the footprints; the footprints project out from the sandstone. The ‘right manus’ of the animal is therefore represented by the footprint on the left side of the track.
  • The differences in shape of the manus prints demonstrate how digits dragged through the sediment, each producing slightly different traces.
Fossil footprints labeled with right and left, manus and pes.
Fossil specimen with footprints labeled.

The next step is to identify the footprints; to compare this specimen to previously described footprints and assign the specimen to a footprint identified in previous studies.

Have any suggestions? Questions? 
Please leave a comment below.

Stay tuned for a future post as the study of Eldon George’s fossil collection continues: follow Parrsboro Rocks on Facebook.





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