510 million years ago during a shadowy, Cambrian time, what
we now call Wisconsin was way south, some 10 degrees below
the equator. The diversity of life then was still expanding,
new forms radiating, with the new forms themselves exerting
new types of selective pressures to further drive evolutionary
processes. The Black Berry Hill site (Krukowski flagstone quarry)
of Central Wisconsin near Mosinee (outcrops of the Mount
Group), was then beachfront property of Laurentia (late Cambrian
- Furongian time), with the burgeoning life forms of the
pelagic environment lying
posits an ancient environment comprising inter-fingering shallow
marine, fluvial and eolian facies.
has many mysteries, and of these, the early venturing of
onto land is one of the most mysterious. Many clues to these
mysteries are buried in the Blackberry Hill site. Recently,
many Ichnofossils, as well as body fossil impressions, were
exposed in its various horizons and studied by a number of
shelly animals are found at the Blackberry Hill site, only
(Ichnofossils) and body impressions of Jellyfish
and arthropods. Apparently,
hard body parts such as trilobite exoskeletons never underwent
mineralization, but were instead dissolved back into the sea.
Besides a few mysterious trackways that can not be named,
finds Diplichnites, Protichnites
and Climactichnites, and
most recently a putative trackmaker arthropod from the enigmatic
Euthycarcinoid or Aglaspid
groups. These fossils were only recently interpreted paleontologists.
But ichnofossils in many ways are more revealing than body
because they can give hints about animal behavior and interaction
in the ecosystem, and in the case of the Blackberry Hill fossils,
possibly the first footprints on land in the fossil record.
Thus, hopefully, the result will be some shedding of more light
on this shadowy period of geological history.
ichnofossils of the Elk Mound Group possibly encode
step toward colonization of the land, an evolutionary trend
that would gain tremendous momentum during the Paleozoic.
is likely that these earliest of terrestrial footprints were
made by animals that could leave the water to the intertidal
areas for brief periods. In so doing, they had a brief reprieve
from marine predators while grazing on abundant microbial