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PTNM Field Trip [intro music]
Jerry: In terms of how, how are fossils found? As you illustrated, going up the ravine here,
if you don't know what you're looking at you can walk over a fossil, you can walk over
a tree. So the first process in the process of discovery is somebody needs to know or
recognize what they're looking at, OK? Once you see that, that's not the end of the story.
If it interests you enough, you might pick it up and take it home and go, "Isn't this
a beautiful rock?" And that might be the end of the story.
But if you're knowledgeable enough or understand that this might be important. I need some
outside validation, then you may take it to someone else that may be an expert and you
might say, "Hey, I found this neat rock. What is it?"
And they might say, "Oh, you know, that's a dinosaur bone. That's a piece of petrified
wood. That's a tooth. That's a rib. That's a jaw." And so that's what needs to happen
and if schools do the right thing, they will give you an understanding, at least, of the
scientific method and a cursory recognition of what fossils look like and things.
But oftentimes when you go to a museum, you see the fossil taken out of its context and
so you'll see it in a museum but you don't have any idea where it came from. One of the
things that's happening today is that you are going to actually see fossils in the ground
in the processes that happen. From discoverers to getting validation of what it is and how
significant it is, to having preparators and collectors from museums come out and then
excavate and bring those things out of the ground. The final process is when you go to
a museum and you see the material. You're in a very privileged position right
now. We haven't ever done this in Prehistoric Trackways National Monument. You're the first
ones that are actually coming out and seeing this material in the ground as we find it.
So the second thing is, why was this found here? Well, as you also illustrated, it's
easier to climb up this gully than it is to climb up that slope. That's why this log was
found. I wanted to get over that mountain. I had already found logs in the canyon bottom,
so I wanted to go on the other side of the mountain and see if there were logs on the
other side. I only walked 25 feet and I found a log here. I never did make it to the other
side of the mountain. I'm now here. Part of the process of discovery is luck.
I climbed this because that's the most logical way of getting to the other side of the mountain
than slipping and sliding and killing myself on that slope. See how all this fits together?
Then the newspaper reporter finds a plant frond right after we were explaining to her
what we were finding in this place. She looks on the ground and there's a beautiful plant
frond. All these are little snippets of the processes
involved in discovery. And so here, we have this huge log. I have no idea how big it is,
because I dug it up a little bit, but as you can see, it's huge. I don't know how big it's
going to be the other way. Then we have more pieces of it here and then there's debris.
Here's a bit of that log, OK? And more of it. Here, we have a section of the log and
it actually broke in two, so you're looking at the inside of this tree. Isn't that cool?
If you want to... Scott Elrick: There's a question for you guys.
You have to answer this. What's the shape of that log if you looked at it in a cross
section? Jerry, if you could hold that up to show how that looks like in a cross section.
What's that shape? Audience Member: Sphere. Oval.
Audience Member: Oblong. Man 1: Yeah, kind of oblong, sort of oval.
What's the shape of a tree? Audience Member: Round.
Audience Member: Circle. Scott: What the heck happened?
Audience Member: It got squished. Scott: It got squished, absolutely.
Audience Member: OK. I see. Scott: Something else. How does a tree, which
is made up of organic material and catches on fire, you can build stuff out of it, how
does it turn into a rock? Audience Member: Just stuff. [laughter]
Scott: That "stuff" is really, really general, but I'll let you go with that. Keep going.
Audience Member: The stuff just forms around it over time, like the sand, the rocks and
stuff like that. Scott: You're right on target. Any other,
some other ideas, anything else? Audience Member: Just the pressure, really?
Audience Member: The climate? Scott: Say again?
Audience Member: The climate? Scott: Climate?
Audience Member: Like the weather, like how... Scott: You're kind of going along the right
tracks on all these things. Where do we get our drinking water from?
Audience Member: The groundwater in the table. Scott: Absolutely. We've got groundwater,
water moves through the earth, right? Right? Is groundwater pure?
Audience Member: No. Scott: What does it have in it?
Audience Member: Dirt. Audience: Minerals.
Scott: Minerals. Bingo. All right. So tell me about a tree. How does a tree grow?
Audience Member: The ground. Audience Member: Its roots absorb water from
the ground. Scott: Water goes through the tree, yes?
Audience Member: Yeah. Scott: Tree's dead. There's still ways for
water to get through that tree, yes? Audience: Uh huh.
Scott: Water's got minerals in it. Water flows through the tree. You have to get the right
conditions it doesn't happen all the time but the minerals precipitate. You heard that
used. I'm sure you know what precipitate is, right?
Audience: Uh huh. Scott: This is a stupid joke. I'm sorry. I
can't help it. [laughter] Scott: If you're not part of the... If you're...
Let's see. Audience Member: If you're not part of the
solution, you're part of the precipitation. Scott: That's right. [laughter]
Scott: You're not part of the solution, you're part of the problem. You're not part of the
solution, you're part of the... OK. Sorry. [laughter]
Scott: Anyway. Water moves through the trees, or through the dead trees. Minerals precipitate
out. That's how you turn these trees that otherwise would have rotted away into fossils.
Audience Member: Fossils. Scott: Silicified. Usually it's silica that
goes through these things, but you can get other things. Jerry, help me out. You can
get more than silica through these, right? Jerry: Yeah, you can. A question even before
his question is notice what we're finding with this log. Is this log in a living position?
Audience: No. Jerry: So it's been separated somehow from
the root system, right? If a tree is separated, what does it do? Does it still stand straight
up? Audience Member: No.
Jerry: No, it falls. This is preliminary even to his questions is you look at the orientation
of this particular thing. I want to bring this up because we do have in the monument
at least one log trunk that's vertical. So that's significant in and of itself, because
it may actually be in living position. Audience Member: How big is the Monument?
Jerry: The Monument is 5,290 some... Audience Member: Acres?
Jerry: Acres, sorry. Brain drain, there. 5,280 some acres or about 12 square miles.
Audience Member: Could it be possible that it extends beyond the monument? The fossils?
Jerry: Oh, yes. I'm glad you asked that question, because I need to point out something. The
difference between a fossil deposit and a fossil locality. Do you think you could anticipate
the answer in terms of what the difference would be between a fossil deposit and a fossil
locality? Any ideas? Audience Member: I would say it's probably
a very great concentration of fossils in a given area; whereas a fossil... What was the
other one? Jerry: Locality.
Audience Member: Locality is one that's just in localized space.
Jerry: OK. I think you're going in the right direction, but let me explain. With a fossil
deposit, and there's another term that comes after the discovery of a fossil deposit, where
the fossils are found actually make up the area. So like, what we're studying here, all
along this marl, this paleo valley, we're finding logs in place. These logs died, were
sunk, and turned to stone, if you will, and buried. So all of the information that we
get in these mountains are important. All of these fossils that we're finding in Prehistoric
Trackways National Monument, the context of all of these fossils are crucial, and especially
the trackways. Some of these mountains are literally made up of the material that have
the tracks. So the whole area is important. Now, let's consider finding a dinosaur skeleton,
for example. Many times you'll find an animal that dies and then it's transported by water
into a place, and that place, in time, doesn't tell you very much else except what it's done
is preserve that skeleton. Once you take that skeleton out, you don't really go back to
that place unless there's just tons of bones everywhere. But I think you understand the
difference now. This is not like finding a happenstance piece
of petrified wood. There's a whole story written in the very mountains that are important,
so we need to have all kinds of specialists. Specialists like Scott, who know geology and
paleobotanists like Bill DeMichele from the Smithsonian and other people that come and
have expertise in all of these areas of science, because we're studying a deposit. An area
that's just rich with fossils. [music]
Transcription by CastingWords