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PaleoLab
Project: Camarasaurus Click on any thumbnail for a larger image in a new window Allen
Shaw I have removed the first dorsal vertebra from the rock and finished preparing it. Unfortunately, not all of the dorsal vertebra was in this block. There are other segments of this block in the Big Bone Room that may contain the remaining portion of the vertebra or its neural spine.
Front & Side Views
Openings of this type reduce weight but retain strength, similar to an I-beam.
Bottom View
Yvonne_Wilson Yesterday I began a new jacket. It is supposed to contain sauropod limb bones including the radius and ulna (forearm bones) and the end of a humerus (upper arm bone) the rest of which Allen prepared out of his last jacket. Here is the unopened jacket:
And I got thus far:
The curious thing is that we see the end of the humerus that we expected, but the bone on the lower right looks like a humerus too. And the third (on the left) might be an ulna. We'll just have to wait and see. Another odd thing about this jacket is that there are 6 paper-wrapped packages of bone that were included in the jacket. I don't know yet how they belong to what is exposed. They may be pieces that came loose while they were wrapping up the fossils, or they may be complete surprises. It looks like they put in little birthday presents for whoever was to prepare this jacket. Okay, maybe not. Allen_Shaw Sauropod Caudal Vertebrae These two articulated caudals (tail) vertebrae were prepared by one of our volunteers. Here they are finished.
Allen_Shaw
In
the lower part of the image is a dorsal vertebra. The damaged dorsal vertebra in this image is located in the upper part of the block. I will try to remove the rock and prepare each individaul dorsal vertebra.
Yvonne_Wilson This end with the matrix attached is driving me bonkers. The grade between the bone and matrix is ever so slight. The bone is the hardness of a cookie, but the rock is so hard I cannot remove it with hand tools. So I am using the air scibe all day and vibrating my forearm and hand nearly to numbness. Sorry to complain so much.
Allen_Shaw At Last!!! I have finally finished this project. It turned out to be an almost complete scapula and humerus with a small portion of anther humerus. I left the scapula in two pieces to make it easier to handle and move. Here are a few images of the final project repositioned in the jacket. See if you can find this block on the map in "a splendid Past" exhibit. It should be located on the far left side of the map under the number 175/M or 175/12. You will also notice that the rest of the humerus is in another adjoining block. Good Luck.
The humerus is on the far right underneath the scapula.
The other humerus (finger) under the other end of the scapula.
Yvonne_Wilson Moving right along, I've got more of the femur together. Here's one end:
And here's the rest (the tower of bone):
.It's going together more slowly than I would like, but administrative gobbledegook took precedence for a while. As in any job...Okay, back to work,
Allen_Shaw Whew!! I am finally starting to see some progress from all the effort I've put into this project. First I removed most of the jacket covering the bones and then the surrounding rock so that I can remove the pieces. For the last few weeks I have been removing small pieces of bone, cleaning them, and then gluing them together to form larger pieces. I can now start to put these pieces together with plaster complete the scapula. Meanwhile, I have also started cleaning and gluing the pieces of the humerus underneath the scapula. In the last week, I also discovered another partial limb bone at the other end of the block. I had a good idea that something else was in this block because of how thick the jacket was on either end. The scapula is only 1/4"-1" thick across most of its length and the block is a good 6"-8" thick. Here is an image of pieces of the scapula being plastered together in the sand box.
Here you can see the partially cleaned and plastered scapula resting atop the humerus.
Although difficult to see, the scapula had another limb bone hidden under its other end.
Yvonne_Wilson
Yvonne_Wilson
This is where I am now on the femur. There is also a tower of bone in the sandbox where I am putting all the chunky pieces together. The bone is cooperating nicely -- the pieces fit well and are not breaking up too much. I just can't wait until I'm done and I have to search in our collections for the end of it. It was prepared out of another jacket a long time ago. Cross your fingers that I find it easily.
Yvonne_Wilson It'a a cool new thighbone (femur) jacket. Just from the shape of it I could tell there is very little matrix on the bone. We could see some bone through small worn patches on the ends of the jacket and the bone looked really solid and hard. That's always good news. But I opened it and it's a bit more broken in the middle than at the ends. For some reason, that's typical. Take a look:
So it'll be a little bit of repair work too. Yeah, but it still looks like fun. I sure like my job.
Allen_Shaw Peter: Here are two articulated caudal vertebrae from a sauropod. The neural arches are broken and separate at present. When repaired they will be attached to the centra.
Allen_Shaw The scapula block is large and heavy enough that the bone hoist was needed in order to lift it onto a table. Here you can see several images of the lift from box to table.
When lifting a large block like this it is important to find a table that will support it and provide just enough space to make preparation easy without having to bend over too much. Also, of importance is placing straps strategically around the whole jacket so it is raised evenly. Once all these factors are considered and taken care of, the lifting process is very quick and painless. Now the most exciting part can begin, opening the jacket. It is often just like opening a christmas present because you will be the first person to see what is inside since the early 1900's and sometimes you will be the first to have seen it in millions of years. Here you can see the jacket opened and the bone exposed. Although it is hard to differentiate between the jacket and bone, what is visible is the largest part of the scapula. The "v" (shown with chisels) at the left of the picture is where the scapula articulates with the upper arm bone (as seen with Diplodocus or Apatosaurus out in the Dinosaur Hall).
Allen_Shaw Upon opening the box, 3 plaster jackets covered with 80 years of coal dust and other garbage were exposed. The jacket in the upper left corner contains a partial femur (upper leg bone) similar to the one currently resting just outside the lab. The long jacket taking up most of the space in the box is a scapula (shoulder blade) with a humerus (upper arm bone) below it. Both of which, are in the same jacket. A small jacket hidden just to the upper right contains two caudal (tail) vertebrae.
After cleaning all the garbage and dust off the jackets, we then physically lifted the femur and placed it on the table to be prepared.
Yvonne_Wilson It'a a cool new thighbone (femur) jacket. Just from the shape of it I could tell there is very little matrix on the bone. We could see some bone through small worn patches on the ends of the jacket and the bone looked really solid and hard. That's always good news. But I opened it and it's a bit more broken in the middle than at the ends. For some reason, that's typical. Take a look:
So it'll be a little bit of repair work too. Yeah, but it still looks like fun. I sure like my job.
Allen_Shaw As preparation of the scapula proceeds, the humerus underneath becomes more visible.
Allen_Shaw This box, dated to the early 1900's, contains several blocks instead of just one large block. The skeletal elements (bones) found in these blocks are a humerus (upper arm bone), a scapula (shoulder blade), caudal (tail) vertebrae, and a femur (upper leg bone). The specimen is tenatively designated as Camarasaurus but we will not know until we open the jackets.
Allen_Shaw AT LAST!!! The large block is finally empty. Although it is empty, the bones removed are still undergoing cleaning and gluing. I will be working on the bones from this block for another week or so. Here is the last image of this big block.
If you look on the quarry map (located in 'a splendid past' exhibit), this block can be found on the far left section with the number 175/I.
Yvonne_Wilson In the basement lab, Norm is making the new cast. He has the upper portion almost done. Just a jaw to go. Yvonne_Wilson The jacket is empty. I have to get this rib off the hunk of rock it's stuck to, plaster the cracks in the rib, and do some final touch-ups to the various bits and pieces from this jacket. Then it's on to a new challenge!
Yvonne_Wilson We still don't have any idea what the top bone piece from this little jacket is. It's flat and has two ridges that we thought might help us identify it, but they didn't really help. So I am left with a UFO (unidentified fossil object). The rock around the rib is SO HARD that I did have to pull out the impact hammer on Sunday. It broke the rock in two but I couldn't get it any smaller than a volleyball. I finally started wailing on it on the floor with the crack hammer. And about half an hour later, just before I wore myself out, it popped. A golfball-sized chunk skidded across the floor to the other side of the room too. Wouldn't you know it that the rock had nothing more in it? Arrgh! The latest find is part of a limb bone. It was split right against the jacket, so we may or may not be able to find it's counterpart either in the collection already or in another jacket if it hasn't already been prepared.
Allen_Shaw Wow!! Talk about a pancake. This vertebra (shown in the previous post) has seen some distortion. Vertebrae are typically round and spool shaped but this one has been smashed and distorted. Notice the thickness of the vertebra and the elliptical shape.
Along with being crushed the vertebra has also been distorted laterally. The opening seen below should be visible in the same area on the other side. Instead, the distortion has closed and moved the opening high up on one side where it is almost indistinguishable.
Allen_Shaw Cool!!! A small (1 inch long) phalange (finger/toe bone) probably from a theropod dinosaur. Finding it was somewhat by chance. As we work through the rock to get to the bone, large portions of barren rock is thrown away. By breaking up these large portions into smaller chunks we make sure that no small fossils are overlooked. This phalange was found as I broke the surrounding rock before I was about to throw it away. Small pieces of bone have been discovered like this before but they often are well rounded and unidentifiable.
Yvonne_Wilson I opened a jacket that arrived in the same crate as Allen's block did back in the 19teens. It may or may not contain Camarasaurus material. The jacket is small -- it only weighed about 385 kilograms (about 175 pounds). What I found immediately was a number of bone fragments by a large crack. The crack probably developed in the jacket either in transport or while in storage. I've pieced most of them back together but the bone isn't complete. I really am unsure what it is yet.
I've also come across two parts of ribs in the matrix. They are very hard and much better preserved than the other bone. The matrix they are in is also much much harder there. I tried to break open a softball-sized chunk but a hammer wasn't enough to crack it. I'm sort of hoping that I have to pull out the air hammer...MMM POWER TOOLS...but I doubt it. It's so hard to avoid breaking the bone using such force. Allen_Shaw At last. This block is coming to a close. As you can see here, there is just one large section of rock left. If you look towards the left of the rock section you will see bone.
This image is a closeup of the bone mentioned above. It is a vertebra of a juvenile or subadult dinosaur. We can tell it is a juvenile because the neural spine is not fused to the centrum. The evidence of this is seen in this image-The corrugated bone surface is where fusion of the upper and lower part of the vertebra would have taken place similar to interfingering and fusion that occurs between bones in our skull as we get older.
Yvonne_Wilson We finished the mold, let it dry and pulled it off the cast. It didn't go exactly as planned. We had to actually use a hammer to break elements on the back of the skull to get the mold off. So those had to be repaired with plaster and paint. The repairs turned out quite well if I say so myself. I got a painting lesson from our Scientific Illustrator, Mark Klingler. (You can see some of his work near the bugs at the rear of the third floor.) I was never much of an artist but the skull looks as good as new. We sent the mold to an outside contractor to make the new cast. It should come back in about two weeks. Allen_Shaw Finally, we have finished the long process of adding latex to the Camarasaurus head. The plaster jacket has been poured over the latex and we are now separating the pieces and pulling the latex off the skull. Finished latex layer being covered with plaster.
Mold pulled off of lower jaw.
Closeup of teeth from lower jaw mold.
Allen_Shaw We have successfully placed a plaster jacket over the latex covered portion of the skull. Once we turned the skull over and cleaned it, we now begin the process anew of adding layer after layer of latex until it is strong and durable on the new sides. Here the skull has been turned over and cleaned in preparation for the top to be covered with latex.
A closeup showing the jacket, latex, and uncovered skull.
Liquid latex just brushed onto the skull.
Closeup of the latex covering the skull. The latex has a consistency similar to elmers glue.
Allen_Shaw Phew!!! I finally made it back to preparing the big block. This last week or so has been exhilarating and nauseating at the same time. A good portion of our time has been used on the making of the Camarasaurus head mold seen under the fume hood. I have placed a few images of what we have been doing with the mold within its own post, so check there for an update. Yvonne_Wilson Allen and I helped out in layering the smelly liquid latex. It takes 20 coats to make it thick enough. When we finished that, Peter had to shape sticky wax against some portions. The next layer will be plaster and burlap, which is very stiff. If it is placed on sections that are underneath the bone at all, when the plaster jacket is pulled off it will take the bone off with it. The sticky wax fills in the areas below the bone so that the plaster won't get underneath bone when it is put on. That way we can keep our Camarasaurus head intact. Allen_Shaw This block contained nothing but ribs until I found this ?dorsal vertebrae. The dorsal vertebra are located along the back. A vertebrae can be seperated into two parts-the neural arch and spine (red) and the centrum (green) (dinosauria.com)
One interesting feature of this vertebrae is the opening up of the internal portion of the centrum. This cavity may have been filled with air, lightening the bone during the life of the dinosaur. This is a view from above looking down into the centrum.
It may have helped the dinosaur but the very thin nature of the bone makes preparation more tedious and difficult. Yvonne_Wilson Allen and I helped out in layering the smelly liquid latex. It takes 20 coats to make it thick enough. When we finished that, Peter had to shape sticky wax against some portions. The next layer will be plaster and burlap, which is very stiff. If it is placed on sections that are underneath the bone at all, when the plaster jacket is pulled off it will take the bone off with it. The sticky wax fills in the areas below the bone so that the plaster won't get underneath bone when it is put on. That way we can keep our Camarasaurus head intact. Yvonne_Wilson
Allen_Shaw Here are a couple of examples of finished bones. The gaps and spaces within the rib have been filled in with plaster after all the rock was removed. The following image shows what the ribhead looks like upon completion. This portion of the rib connects directly to the vertebral column as seen on the mounts in dinosaur hall.
Yvonne_Wilson Today I am plastering the gaps and holes in the bone. We color plaster with poster paint and pour/wipe/scoop it into the spaces. The plaster helps to support and hold the bone together. Once the plaster dries, I take off the excess by scraping with a pin vise or by scrubbing with a toothbrush. It's sort of messy, makes colorful additions to your clothing, and tends to poof up your nose when you least expect it. Okay, but it is fun. Allen_Shaw The slowest and most tedious part of the whole preparation process is the removal of the last vestiges of rock still adhering to the bone. I have finished the preparation on two of the ribs removed earlier and now I am working on the removal of another rib from the block and final prep of the caudal (tail) vertebrae. Allen_Shaw At last. With the completion and filling of our large sandbox, I can begin to put the larger pieces of bone together without them falling over. Final preparation of the bone is accomplished by placing plaster within any cracks or gaps. Primarily, the plaster strengthens the bone and secondarily makes it look more presentable. Once I have finished glueing and plastering the elements removed from the jacket previously, I will then continue to remove more bone. Yvonne_Wilson Latex, latex, stinky latex... It's a good thing that we have a fume hood in the lab that exhausts any harsh smells outside. Peter has been painting layers of liquid latex onto the skull. Each layer has to dry before the next is added. It stinks and it takes a stinking long time. When enough layers have been applied, he will make a support for the flexible latex in order for it to hold its shape. The support is often a plaster jacket just like those that protect the fossils while they are in transit from the field. You can see these in the lab. They are burlap layers soaked in plaster. But in the meantime, we suffer with the stinky latex. Yvonne_Wilson Surprise, surprise! I thought I was just delving into the final touches, working on some loose blocks from within the jacket. It turns out that I had another projection from my vertebra tucked inside one of these blocks. It didn't look like anything much on the surface, just some scrap bone that really wouldn't be missed if it were tossed out. I kept scraping away and revealed 3 dimensional curves. Much more than I expected from the loose blocks. It's a nice addition, but unfortunately, since I don't have a good contact point between it and the remainder of the vertebra I have to leave this new find loose beside the bone. You can't guess at the contact because you might be dead wrong. Still, it was a nice find for the day. Yvonne_Wilson Once the vertebra was freed from the rock and the jacket, it was time to glue all the loose pieces together. Once I finish that, this project will virtually be done. It will likely need a little bit of final clean up, but then it will be done! Yvonne_Wilson The bottom 3 inches of plaster were not empty but held what is 90% rock, not bone. So I went to a good amount of trouble for not much payoff. I had to cut into the jacket with the cast cutter, chisel off the layers that the cast cutter could reach into, then cut into more layers. Repeat this process about twenty times and you free the rock! Those guys sure knew how to protect a fossil -- the plaster was often two inches thick. Allen_Shaw The vertebrae I found before is fractured into many pieces making the preparation of it quite difficult. One interesting feature of this vertebrae is that it is hollow with thin struts of bone strengthening the exterior. The bone is very thin (1/8th of an inch) in places and quite brittle. The pieces are first put together and then the rock is removed from the outside of the vertebrae. Allen_Shaw At last, something besides ribs. Within the last couple of days I have begun to uncover what appears to be a caudal vertebrae. If my initial identification is correct, then this vertebrae would have been located towards the middle of the tail of Camarasaurus. Allen_Shaw Interesting...I have uncovered another ribhead with a good portion of the rib with it. The last two or three feet of the rib appear to be lost during field collection. This ribhead is larger and more robust than the first one. The rib itself is about 5 inches wide and at least an inch thick. The strange thing about this rib is that there are still sections of the head that are very thin and I am unsure if this is a feature seen in the individual Camarasaurus or a product of erosion. Yvonne_Wilson The backbone cleaned up fairly well. I decided to flip the whole thing and solidify/glue it from the backside. I thought that I had it all together...when I flipped it, a lower layer came off with the jacket. That layer was strangely separated from the rest of the fossil by a piece of canvas. I don't quite understand why the original collectors did this. Now I have to keep gluing the bone, piece the stubborn jacket-hugging layer back on, and do some final clean up. This project shouldn't last forever. I want to crack into the three inches of lower plastar to see if it holds anything or if it is just an insurance policy for the specimen. We'll find out. Allen_Shaw Once I have finished glueing all the pieces together I will fill in the remaining openings with plaster to add strength to the bone and make it BEAUTIFUL . Allen_Shaw The ribs are finally going together into good sized portions that can be easily managed. I am continuing to remove rock from the block and in the process uncovering more ribs. It is amazing to me that so many ribs are found in this one block. Within previous blocks, ribs were found entangled with other more robust elements but in this block there are only ribs (so far ). The ribs being removed are all different sizes and shapes (probably representing many different locations and portions within the dorsal area of the skeleton). Yvonne_Wilson By attacking from a different direction, I was able to trace the rim of the bone that seemed to grade imperceptibly into the rock. The edge of the vertebra is very thin and fragile. And of course the matrix is very hard, which makes is particularly fun! Allen_Shaw I finally removed the ribhead and in the process uncovered more bone...probably a rib. Now I will proceed to clean the ribhead and glue all the many pieces back together. I was reminded the other day that my little sand box looks like a mini stonehenge with all the bones I am glueing together. Allen_Shaw There are a plethora of ribs in this jacket. It seems that when I remove one another is quickly found to take its place. I am currently preparing the bone I removed earlier. It is a tedious process of removing matrix and constantly glueing pieces of bone back together. During this process it is very important to always reduce the number of small pieces by glueing them together as soon as they break off. Otherwise the number of small pieces builds up and one forgets where they once went. IT IS FUN!!! Yvonne_Wilson In the same crate as Allen's Camarasaurus rib jacket, there were packed two smaller jackets. The smaller one was not entirely encased in plaster. The fossil collectors left the top open to the air. Remember that this was collected back in the 19-teens or so. Pittsburgh was soot city. I had 80 years of soot and dust built up on the top surface of my project. It discolored the matrix and made the bone hard to see. After vacuuming off and staring at the jacket for a long time, I realized that the jacket is mostly bone. It is a dinosaur vertebra. The top surface held a jumble of loose blocks of bone. I've been trying to piece them together with limited success. The matrix itself is hard, but not terrible to work with. With the airscribe it comes off rather quickly. My only problem is that one portion of the bone is the identical color to the matrix. I almost feel like I'm guessing at the bone margin at that point. It just sort of grades into the matrix with no definitive outline. It's a challenge... Allen_Shaw Peter started making a latex mold of the adult Camarasaurus head. We will be displaying a touchable cast of this in the area outside the PaleoLab. The first step is to create a "dividing flange" that will form the boundary of the two halves of the mold. Then he will paint layers of latex on the specimen and flange. The whole process will probably take about 6 months working between 6 and 10 hours per week. Allen_Shaw As for the preparation of this block, it is proceeding with some difficulty. Some of the bone is about 1/8th of an inch thick while other bone was lost during collection. By removing the ribhead I uncovered more bone that is also in desperate need of attention. As it stands now I am still engulfed by ribs. Allen_Shaw Interesting...One of the ribs is actually a complete ribhead (the very top portion of the rib that connects to the vertebra).
Allen_Shaw Hmmmm... The field notes of Earl Douglas describe the contents of this block as being indeterminate. That description fits very well with the fragmentary bone showing up within the block. With the removal of rock, a number of bones have begun to appear. Upon first examination these bones appear to be ribs of varying size and thickness haphazardly oriented within the rock. Ribs, ribs, and more ribs!!! Ribs provide very little information about the type of dinosaur represented so are not very exciting to work on. This block will require lots of rock to be removed to find any substantial remains like vertebrae or limb elements but for now the ribs await.
Allen_Shaw I am new to Pittsburgh and its amazing paleontological history. I will be working on dinosaurs within the lab. I recently opened a new block containing what is thought to be elements from Camarasaurus. As you can see, there is very little bone exposed and not enough to properly identify what skeletal elements are showing. The bone that is showing is tan to dark brown in color with a redish brown "rust" stain surrounding it within a greenish gray sandstone matrix. You can see this on the edge of the block closest to the window. As I continue to prepare this block, I hope to encounter more substantial remains of Camarasaurus, so stay tuned. Return to Preparator's Journals
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