PaleoLab

Project: Camptosaurus

More Camptosaurus Logs: Summer 2005 | Spring 2005

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February 24, 2005 05:30 PM
posted by Yvonne Wilson

As I was outlining above the jacket, near the neck, I started finding something that looked to the naked eye like bone. Now it just so happens that the plaster used to fill in cracks and such on the dinosaurs can look just like bone under certain conditions. Turns out what I had found was plaster, but what in the world was it? I should have been away from any portion that needed to be repaired or patched with plaster.

I uncovered more or this dark plaster as I worked further from the body, but then it was suddenly covered by wire mesh and more plaster. Eureka! I had discovered the original skull that was mounted on this body. The skull outline is nearly impossible to make out, but this was how I found the mesh over it.

2-23-05 Camptosaurus outlining torso exposed wire net.JPG


If you look at this picture of Camptosaurus as it was originally mounted in 1925, you can see the head was bent back against the body. That skull outline, which is just a profile in plaster, is what they had covered up with wire and more plaster when they remounted the skeleton around 1934.

Camptosaurus original mount.jpg

The skull is now a scrappy version of its original appearance, unfortunately. They even drove nails through it to attach the wire mesh. For them, it was just something to cover up. I wish I could still have it all together, just for fun.

February 23, 2005 10:13 AM
posted by Yvonne Wilson

The second to last task before laying the case down is to completely outline the portion that will be removed. This outline is an etching, not just a drawn line. The purpose is to make it as easy as possible to get through the "wall" of the case once we lie it down. Afterward there is little holding the jacket in place. As I went around the torso I realized that the original mounters had left the lower (right) rib ends hanging out of the jacket. This is not safe. I decided to wrap another layer of plaster and burlap around the rib ends, leaving a little plaster buffer so they won't break.

Here you can see some of the experimental holes I drilled to find the extent of the rock within the mount:

2-23-05 Camptosaurus outlining torso pelvis.JPG


This is all that is left of the body:

2-23-05 Camptosaurus outlining torso edited.JPG


The plaster in some places is preposterously thick.

2-23-05 Camptosaurus outlining torso ribs post.JPG


As a filler material, they mixed wood shavings into the plaster. It lightens the case, but frustrates me. The airscribe has nothing to bite against (the wood just mooshes), a chisel likewise just crushes the fibers, so the only efficient way to get through this material is with a drill. But the drill doesn't like the wire mesh behind and within some sections, so I have to keep switching tools back and forth to find something that works. ARRRRRGH!

The confounded wood shavings:

2-23-05 Camptosaurus outlining torso filler fibers.JPG

February 13, 2005 04:44 PM
posted by Yvonne Wilson

Back to business on the tail. My arms have had their day's rest. Because it is a largish block of tail vertebrae, it takes a while to etch all the way around it. I had to define where the real rock ended and the plaster started.

And though they are fake, it was still emotionally difficult to cut right through the portion of the tail that we shall discard. This part is just sculpted as relief elements straight onto the plaster wall.

You can see the backing wire mesh showing through on the left, and where I had to cut through the fake tail parts near the bottom of the picture.

2-11-05 Camptosaurus caudals removal 2.JPG


Finally, after also cutting through a metal rod embedded in the plaster, the block of tail vertebrae comes out in one piece. Free at last! Notice that the central four vertebrae are connected at the top by a higher grey lump. This lump is the real, cement-hard rock. The other vertebrae are mostly held together by plaster. Thus the first and last bones will be much easier to deal with than the central vertebrae in this block. Cross your fingers for me. The neural spines are long, thin, and fragile. These are the blades that stick up on each bone -- you can feel one on your own backbone if you touch where your neck meets your back.

2-11-05 Camptosaurus 4-13 caudals lat.JPG


And today, Allen removed the ribs that are not embedded in the rock. They, like the shoulder blade, are supported by a metal rod protruding from the back wall. Each rib is very fragile, and the 80-year-old plaster tends to break often. The plaster I refer to here is what the oldtime preparators used to glue together the broken rib pieces. So many of the old breaks are rebreaking as we handle the material. This view shows the rod supporting the brown ribs.

2-09-05 Camptosaurus left dsl ribs.JPG


Allen examines what remains of our Camptosaurus.

2-12-05 Camptosaurus exhibit and Allen 2.JPG


February 12, 2005 05:51 PM
posted by Yvonne Wilson

Allen moves on to the neck of the Camptosaurus. In the original 1925 mounting, the neck was left in its "death pose" bent back against the body.

campto1.jpg


A few years later, perhaps as late as 1940, they decided to tilt the whole creature, change the tail and the head, and straighten out the neck. This is the pose that we are familiar with from Dinosaur Hall. When they moved the neck position, they took out the individual neck vertebrae, plunked them into plaster as a unit, then plastered this island between the new head and the torso. Just as a reminder, this is the pose from Dinosaur Hall, just before we started taking the skeleton apart.

1-13-05 Camptosaur case front 3.JPG


So Allen has the altered series of cervicals (neck bones) to remove from the plaster mount. He etches around the neck with a powerful chisel-tipped airscribe
that cuts quickly through the plaster.

2-09-05 Camptosaurus cervicals removal 3.JPG

The series of neck bones comes out in one block. Surprisingly, when Allen removes the vertebrae, there is still some real rock left on them. They removed (or prepared) the rock from the side of the bones that showed, but not from the other side. I suppose they were in a hurry to get it remounted. In the following picture you can see a base layer of white plaster that secured the island of bones to the mount, topped by the layer of grey rock-colored plaster, which was topped with pebbles after the bones were set in. If I say so myself, they did an excellent job imitating the original rock. It can be difficult to tell them apart sometimes unless you break into the layer of plaster.

2-11-05 Camptosaurus 2-7 cervicals dor close 3.JPG

February 11, 2005 03:18 PM
posted by Yvonne Wilson

Getting tired of holding my arms up so high, I work on a different body part for the day. I take out the left hand, which is real. The right hand was sculpted because it was not found with the skeleton. They articulated, or put together, the individual bones of the hand. This made it easy for me to remove. I etched away the plaster in a circle around the hand, and the hand plus the plaster they embedded it in came out as one.

2-09-05 Camptosaurus L manus 2.JPG


Interestingly, they didn't get the hand quite right. A visiting researcher who has been examining the specimen as we have been taking it apart found one or two of the wrist bones were incorrectly placed in the plaster.

So the Camptosaurus loses yet another body part.

2-09-05 Camptosaurus L manus removed.JPG

Meanwhile, Allen has been working on the scapula -- the shoulder blade. It is resting on a steel rod for support. It is also attached at the back end to the rock. Not an easy task to approach, because its thin blade is very fragile. I had started the work on this area, but found I was too short to effectively reach the point of attachment. Holding a mirror to see what I was doing was a bit awkward. Allen, good man that he is, offered to take over. Even he had to stand on the stepstool to gain access to the bone.

2-09-05 Camptosaurus left scapula removal close.JPG

After he takes it off:

2-09-05 Camptosaurus left scapula removed 2.JPG


February 10, 2005 05:56 PM
posted by Yvonne Wilson

While Allen finishes up the limbs, I begin work on the tail. Only about 2 feet worth of tail is real bone. The rest is plaster reproduction. We can see where the real bone ends, but finding where the rock actually ends is another matter. When they created this panel mount, they smeared plaster and pebbles (a simulated rock surface) over everything except the bones. The real rock is hidden. So, as a physician performs exploratory surgery, I poke around with an airscribe, or sometimes a drill, to figure out where the rock is beneath the plaster surface. I have to wear gloves because the pebbles rough up your skin pretty badly.

2-09-05 Camptosaurus Yvonne removing 3rd caudal.JPG


The first few tail bones are only in plaster. Once I've located where the rock begins, I start working out the vertebra just in front of the rock in order to make room to move. It is a tight fit between the vertebrae and as such may take a bit of work to remove.

2-09-05 Camptosaurus 3rd caudal removal.JPG

February 09, 2005 11:16 AM
posted by Yvonne Wilson

Camptosaurus is disintegrating! Or should I say disarticulating? Allen's next move to disarticulate the skeleton is to take out the right humerus, or upper arm. It is lying partly in the plaster, so Allen etches around the bone with an airscribe.

2-08-05 Camptosaurus R humerus removal.JPG


And here you can see the remaining body without the upper arm.

2-08-05 Camptosaurus R humerus removed lat.JPG

February 04, 2005 11:05 AM
posted by Yvonne Wilson

As we go farther with the project, each bone is deeper within the plaster. All the bones that were just "tacked on" with dawbs of plaster are gone. Continuing with the leg removal, we etched out the plaster surrounding the right femur, or thighbone.

1-29-05 Camptosaurus R femur being removed close.JPG


And once it is freed, the Camptosaurus looks pretty funny.

2-02-05 Camptosaurus R femur removed 2.JPG


The thighbone itself, 150 million years old.

2-03-05 Camptosaurus R femur medial view.JPG


Allen has taken out the lower leg from the right side. You can see the gloopy plaster still stuck to the bone here.

2-04-05 Camptosaurus R tib fib lateral view.JPG


The emperor may have no clothes, but the Camptosaurus has no legs!

2-04-05 Camptosaurus R tib fib removed.JPG


February 02, 2005 10:20 AM
posted by Yvonne Wilson

Believe it or not, this unassuming piece of bone (to the left of the diagonal pipe) is the result of several days' hard work on the back of the Camptosaurus case. It is part of one of the dorsal (torso) vertebrae. It demonstrates to us that the bone within the rock is in good shape, and that the rock comes off cleanly. If the bone had been crumbly, crushed, or too difficult to remove, we would have scrapped the idea of making this dinosaur into a 3-D skeleton.

1-29-05 Camptosaurus exhibit back dorsal tp.JPG


While I was working on the back of the case, Allen kept pulling the Camptosaurus to pieces. He removed the left arm as two pieces, upper and lower.

1-28-05 Camptosaurus L humerus ant view.JPG

1-28-05 Camptosaurus L radius ulna 2.JPG


"Where's my left arm?"
1-28-05 Camptosaurus L radius ulna removed.JPG

January 29, 2005 04:58 PM
posted by Yvonne Wilson

After the fun surprise, I had to get back to business and open the back of the fossil jacket. We estimated where an interesting portion might be within the rock and I went to work. They made the protective jacket and supports very strong, so it will be a chore just to get to the rock.

1-28-05 Camptosaurus back open iron rod Yvonne.JPG

First, there is a 3 inch thick board to cut through. I use a reciprocating saw. Then there is a thick layer of plaster that attached the board to the fossil jacket. Using a cast cutter, hammer and chisel, and a big ole' airscribe (like an engraving tool, or a dental drill) does the trick.
1-28-05 Camptosaurus back open plaster Yvonne.JPG


Within this plaster, oh boy, I discovered an iron support rod. In the following picture it is a dark horizontal line near where I am chiseling. I think I can work around it.

1-28-05 Camptosaurus back open iron rod 2.JPG

Behind the plaster and the rod is the grey, pebbly rock. It is very hard stuff. I begin to think this will be a very difficult project. In the end I find a second, almost vertical iron rod and finally have to cut through the first one.

Eureka! I found it! The hole in the center is actually a cavity in the rock matrix. My job on the back may be nearly done.
1-28-05 Camptosaurus back open rock prep 3.JPG

January 28, 2005 04:19 PM
posted by Yvonne Wilson

Our dinosaur curator, Matt Lamanna, asked us to check out the quality of the bone on the "underside" of the specimen. Before we went to the point of no return here, we wanted to make sure the fossil would hold up once it is taken out of the rock. This means we have to go through any supports for the bones, and through the rock to see the bone from the other side.

We opened up the back fully:

1-28-05 Camptosaurus exhibit back removed .JPG

This is the "jacket", or the plaster and burlap package in which paleontologists wrap their fossils in order to ship them home from the field. Some bones were never removed from the original jacket, or they were rewrapped later for some reason. There is a large board supporting the back of the jacket.
1-28-05 Camptosaurus exhibit back removed jack exposed.JPG


Hey, what is this????
1-28-05 Camptosaurus exhibit back Allen w bottle 2.JPG

A close up:
1-28-05 Camptosaurus exhibit back removed w bottle close.JPG

They left us a message in a bottle!

1-28-05 Camptosaurus exhibit bottle and note 2.JPG

The workers who put the exhibit together left a note saying where and when the specimen was found (northeastern Utah, 1922), and who worked on the mounting project in 1925. In a second handwriting there is a notation that the exhibit was taken out and "lighted" in 1934. It's a tiny time capsule!

January 27, 2005 03:20 PM
posted by Yvonne Wilson

The most accessible bones are now the left hip bones. The hip is comprised of three bones -- the ilium, ischium, and pubis. The pubis and ischium are mounted very closely, and can come out as a unit.

Allen removed the left, I did the right, and here are before and afters:

1-19-05 Camptosaurus L femur removed 3.JPG

See? The skeleton is slowly disappearing....

1-27-05 Camptosaurus with Left and Right pub isch removed 2.JPG

January 19, 2005 02:37 PM
posted by Yvonne Wilson

So we have begun taking off the "easily" removed pieces. Allen took off the left femur (thighbone) first. These are before and after pictures:

1-18-05 CamptosaurusL femur.JPG

1-19-05 Camptosaurus L femur removed tibia.JPG


With an up-close picture of the knee joint after having done just a little testing here and there in the plaster with the airscribe tool. (The grey object is the hose to the dust collector.)

1-18-05 Camptosaurus L femur tib joint.JPG


Once removed, Allen found that there was still some original rock left on the fossil, and that they had smeared plaster over divots on the bone, trying to "make it look pretty". A view of this bone after preparation:

1-20-05 Camptosaurus L femur ant.JPG

January 18, 2005 12:08 PM
posted by Yvonne Wilson

The next confrontation to this specimen is on the front, not the back. When this specimen was first prepared, some bones were left in the original rock, uncovered only on the one side. Some were completely removed from the rock and set in again attached only with plaster. Some bones have a little bit of plaster, and a little bit of rock attaching them in the case. It's a mixture. Here you can see the left shoulder blade and upper arm are protruding from the "rock" face.

1-13-05 Camptosaurus closeup anterior angle.JPG

And the pelvis here looks sort of jumbled, but by the shadow you can see that some of these bones are no longer in the rock at all.

1-13-05 Camptosaurus closeup pelvis 2.JPG

This view is looking from under the dinosaur's belly up. The ribs are sticking out of the rock, attached with plaster in front. Farther toward his hips, the ribs have been left in the original hard rock matrix.

1-13-05 Camptosaurus closeup rib cage ventral.JPG

And, lastly, a view of the Camptosaurus' left thighbone, or femur, and his hips. The femur had been removed and reset with the skeleton attached only with plaster.

1-18-05 CamptosaurusL femur.JPG

So our first work on the skeleton will be to remove those bones that are attached only with plaster, and those that are sticking out from the face of the rock/plaster.

January 14, 2005 11:47 AM
posted by Yvonne Wilson

Now that the case with the Camptosaurus is in the lab, there is much work to be done. First the carpenters removed the glass covering (thanks guys!). We are interested in the back of the case because we don't have any information on how the skeleton is supported in the plaster.
How we first saw the back (pretty nondescript):

1-13-05 Camptosaur case back.JPG

Here is Don, one of the carpenters in the exhibitions Department, helping us take apart the tongue and groove paneling on the back of the case.

1-14-05 Don opeing case back.JPG

Allen got a little farther and we could start to see something odd. The supports inside are all at a funny angle to the case. Why would they make it that way? It's a mystery for now.

1-14-05 Camptosaurus case back open w Allen.JPG

January 13, 2005 05:20 PM
posted by Yvonne Wilson

We have taken the Camptosaurus that has been in Dinosaur Hall since 1925 and moved it into PaleoLab. The skeleton is mounted into a wall panel. Instead of rock, it is largely encased now in plaster. Our goal is to free the fossil in order to make a free-standing mounted dinosaur, like the ones that stand in the middle of Dino Hall. This is the start of it. Look closely: a head, four limbs, a long torso and a long tail. Much of this will disappear soon.

1-13-05 Camptosaur case front 2.JPG

There is still original rock, or matrix, surrounding the torso. This rock, from the Morrison Formation (layer) is known to be extremely hard, sometimes harder than cement. That could be part of the reason that the original workers left this specimen mostly embedded in the rock. Another reason, though, is that it is nicely articulated, that is, the bones are still in place as they were in the body. We will see how difficult this dinosaur is to work out. I can only hope it will cooperate.


More Camptosaurus Logs: Summer 2005 | Spring 2005

 

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