This
unique Cambrian inchnofossil comes out of a sensational
sandstone formation in Central Wisconsin that was once a tidal
beach, resulting in the distinctive ripples you see on the matrix
surface. At present, it is generally accepted that the age of this
sandstone unit is Middle Cambrian and thus represents an outlier
of the Mount Simon Sandstone. This quarry has been producing some
intriguing trace or ichnofossils, including huge madusae,
tentacled jellyfish, Diplichnites,
Protichnites,
and the Climactichnites
you see here, among others.
The
depositional environment in this quarry varies from very shallow
marine to aerial. This is very significant as the ichnofossils from
this locality may be the earliest evidence of large organisms and
carnivores abandoning their marine habitat to utilize the terrestrial
environment. If verified to be Middle Cambrian, these ichnofossils
may pre-date the Cambrian-Ordovician trackways from Canada just
described in the May 2002 issue of Geology.
Climachtichnites
has been described as looking like the track of a motorcycle that
drove across rippled sand. The ripples in the sandstone confirm
that the layer is an upper bedding plane. If Climachnichnites is
a trackway, the traverse ridges can be viewed as made by muscular
undulation as the animal motivated through the sand above the water.
Also note the ridges on the margins on the tracks, the same as the
ridges that build on either side of blade of a bulldoser. One theory
of Climactichnites is that it was made by a large slug, others believe
a mullusk, and still others posit an animal in an unknown Phylum
that did not survive much beyond the Cambrian.
This
particular specimen is among the better Climactichnites fossils
to emerge from the quarry exhibiting multiple tracks, some superimposed,
and oriented in multiple directions. The multiple trackways essentially
cover the large, heavy sandstone matrix.
Also
see: World's
best climactichnites
|