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>> This is a dinosaur footprint.
The animal that made this footprint was an iguanodon-like
dinosaur that lived 100 million years ago.
The footprint tells us a lot of things about the animal.
These are trace fossils again just
like the tree branch there's no bone preserved here
at this site.
But the trace fossils of the footprints help us work
out a lot of details about the creatures that made them.
The iguanodon-like animal that made this was probably 30,
35 feet long, weighed 3, 4 tons -- an elephant maybe 2 tons
and 20 feet so they're pretty good sized guys.
This happens to be the footprint of the hind limb of the animal.
Now, it turns out that the iguanodons walked on all 4's
and his back hind limbs that gives us the large, flat,
blunt toed impression.
But he walked on his knuckles too.
And his front limbs had a thumb spike
so when the animal walked he walked sort of on his knuckles,
hind leg and then when he brought the thumb
down it made a spike, hind leg, thumb down
and so on and so forth.
So from that sort of information we can tell how large the
creatures were and we can tell how fast they walked,
and when we look at a site like this we can see
that there are certain other things we can find out such
as the size of the prints suggest that --
we have big prints and small prints,
suggest that there were babies walking along with their mamas.
If you look at the small track you'll find the babies don't
seem to have thumb spikes associated and this suggests
that maybe these guys were up on their back feet trying to keep
up with mama as they moved down the freeway.
The fact that we have quite a number
of footprints all different track ways together suggests
there were some herding instincts, so all of this kind
of information can be determined
by close examination of the footprint.
Now, it's important to remember
that the dinosaurs did not walk uphill.
If you recall from the principle of original horizontality
when the dinosaurs walked here, in fact, during the cretaceous,
these were, in fact, flat lying beds.
The question is these are sands, how did the dinosaur walk
on the sand, and after he left how did the sand keep
from being washed away?
And the idea is this, there was a layer of mud on top
of the sand layer and when the dinosaur walked he walked
pressing down on the mud that transferred the footprint
through to the underlying sand and it's preserved
because there's a mud layer on top of it.
Now, this site is one of a number
of sites all along this part of the cretaceous world.
These tracks are -- similar tracks were found in New Mexico,
they're found as we go south of here
in the Prairie Park area along the Front Range.
These tracks are valuable trace fossils
that give us considerable information about these animals,
how they lived and how they --
and their various instincts, what they ate.
It's all information that comes from the rocks
and our understanding of the environment
of deposition during cretaceous time.
