Oldest Known Footprints

[Richard W Travsky <rtravsky@uwyo.edu>]

"footprints" used in a liberal way...


http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2002/06/04/MN46590.DTL

Scientists investigating an abandoned quarry in Canada have found what
appear to be the oldest known footprints of terrestrial creatures --
foot-long critters resembling modern bugs that crawled from the sea onto
land and left tracks in dunes.

The sandstone is 480 million to 500 million years old. Scientists believe
the discovery region -- just north of Lake Ontario outside Kingston,
Ontario -- was a sandy beach on a primordial sea.

The find, the scientists say, pushes back the colonization of land by
about 40 million years and puts it in or near the late Cambrian period,
when the seas were starting to roil with large creatures.
...

The scientists said the Canadian find includes more than 25 trackways that
crisscross an area roughly the size of a basketball court. Some of the
footprints are deep enough to cast shadows.  Typically, the trackways have
a central area where the body and tail made impressions as the animal
moved forward, and parallel areas where rows of legs left multiple
footprints.

Trackways of several sizes indicate the presence of several individual
animals over an extended period, the scientists wrote, implying a "group
exodus from the water."
...
What kind of creatures made the marks? The scientists suspect they might
have been euthycarcinoids -- rare fossil organisms whose segmented bodies
included protective outer shells and long legs.

"There were at least eight pairs of walking legs," MacNaughton said. "We
see the drag marks left behind but can't say for sure"  what animal made
the sandy imprints.
...
The discovery is described in the May issue of the journal Geology by
MacNaughton and five other Canadian and British scientists.