Crinoids’ Stems-Evidence of Fertile Seas, Long
Ago
At this location millions of years ago life flourished in a
shallow sea. During this time there were no multi-celled life forms
living on land, all “advanced” life was contained in the watery
realms and sub-seafloors. Life other than some forms of bacteria
would not appear on land until about 300 million years ago. This
was during the Paleozoic Era, the end of which saw the greatest
mass extinction of animals in the history of the world. During part
of the Paleozoic Era the rocks at this location we see today would
have been composed of soft sediments and sand. During this time
there was an “explosion” of life on Earth in terms of diversity. It
seems that Nature was in an experimental phase to see what forms of
life worked well, and what did not.
At the end of this Era during the Carboniferous Period the great
seams of coal were created from the abundance of plant and animal
life that flourished in these regions. This Period is divided into
the Mississippian (Lower Carboniferous) and the Pennsylvanian
(Upper Carboniferous) time periods. The Mississippian Period was
responsible for the limestones we see in this area, while the coal
has its origins in the Pennsylvanian.
The crinoids pieces seen at this location indicate that they
were one of the most abundant life forms present in this area, at
that time. These animals were filter-feeders and some species
survive even today (see the photo above). Some were believed to
have attached themselves to the sea floor on rocks or corals, while
others may have drifted on floating debris.
The parts that became fossils were the hardest parts of the
animal. Each circular section was just one of many, one on top of
the other making each animal up to a few inches long. The hard
shelled animals such as Brachiopods (similar to clams or oysters)
stood the best chance of becoming fossilized. As the animal died
and settled to the bottom they were perhaps covered with sediments,
encasing the body in mud or sand. When the shell or body finally
deteriorated (rotted) this left an impression or cavity in the
sediments. As time went on the cavity became filled with other
sediments or minerals making a cast of the original animal or
animal part. This is what we see here, and in the photograph
below.
The soft-bodied animals (worms, etc.) or parts of an animal were
less likely to become fossilized. These were usually either crushed
by the weight of the sediments above or decomposed too quickly for
the sediments to compact and form the necessary cavity.
Please note that we have added the "Recommended for
Children" and the "Available During Winter" attributes. Just be
careful with children, this site is close to a cliff/highway/road
cut, and if there is snow covering the ground you will not be able
to see the fossils.
Qualifications for credit:
To get credit for this EarthCache, email the answers to the
following questions and then post a picture of you with your GPSr
similar to the one above (the one with Ammosuperdog and 0.5
Ammosuperman above) when you log your find. We will not accept
pictures of just hands and GSPr units, so don’t be shy. Posts with
no pictures or without emailing the answers will be deleted.
Questions:
1. Find and identify one other type of fossil at this location.
Choose the best answer from the following list. A. Dinosaur bones.
B. Fossilized amber. C. Fossilized fern leaves. D. Fossilized
Brachiopods. E. Fossilized ‘possum teeth. F. Other: if so, what is
it?
2. Why do we not find fossils of soft-bodied animals as often as
those of shelled or hard-bodied animals?
3. What is the elevation at the given coordinates?
If you park closer to the bottom of the road cut it will
be easier to walk to this location than if you try to climb the
vertical surfaces near the coordinates.
Credits and Ammosuperman EarthCaches:
This EarthCache was created by a team of two Platinum EarthCache
Masters, Ammosuperman EarthCaches are a collaborative effort. We
have used resources such as the Internet and magazine articles as
well as personal experience in visiting the sites, as research
tools in its construction. Our goal is to learn more about our
planet and to pass along what we have learned to others having
similar interests. We hope you enjoy the experience.
