I am restoring the Dryosaurus skeleton. This involves filling the cracks and resculpting the broken or missing parts. I use a two part epoxy puttty which can be worked for about an hour and then it sets hard. After this it can also be carved and sanded. If a particular bone is missing hopefully I have the opposite- side bone. I can then model a mirror image replica to represent the missing bone. Here are some photos showing different bones from Dryosaurus in the restoration process.

left and right femurs (thigh bones)

left and right phalanges (toe bones) ...three toes per foot

left and right humerus (upper arm bone) and radius (lower arm bone)

I have finished preparing Dryosaurus. Dan will continue to restore various elements for Dryosaurus along with sculpting missing elements. Norm will continue to mold and cast all the elements as Dan finishes sculpting or restoring them. There is still much left to do with the Dryosaurus skeleton but now that prepartion of Dryosaurus is complete, my priority has shifted to preparing Corythosaurus.

Norm has been molding and casting elements as we have finished preparing and restoring them. Here you can see additional aspects of the molding and casting process.

Elements from the ankle in clay ready for the layer of silicon rubber to be applied. The fossil piece is on the left and the sculpted one is on the right.

One digit from the foot of Dryosaurus in wax.

Finished molds and casts of Dryosaurus metatarsals (foot bones).

Dryosaurus altus

The hand of Dryosaurus is known from only a few specimens with no specimen containing a complete hand. Our specimen may have the most complete hand for Dryosaurus. We knew that the right hand of Dryosaurus in our wall mount contained fossil material but until it was prepared it was almost impossible to tell what was fossil and what was cast.

Can you tell which of these many elements from the hand are fossil and which are cast?

Dryosaurus hand after preparation. The fossil material is white to light gray and the cast material is brown in color.

Norm has already begun molding the elements that do not need any work done on them. Dan continues to sculpt mirror images of elements we need from the opposite side of the body. I am nearing the end of the preparation of the Dryosaurus material and will begin to help either Dan or Norm.

Here are a few images of Norm's progress so far.

Setting the elements in clay before the mold rubber is applied.

Rubber has been applied to both sides of the elements.

Finished mold with both halves and the element used to make the mold.

Preparation continues on both our collection material and on material loaned to us from other institutions. I have prepared all the vertebrae from our specimen and the specimens from the Yale Peabody Museum and laid out the entire vertebral column.

Neck and back vertebrae.

Pelvic and tail vertebrae.

The dorsal (back) vertebrae were a bit tricky to prepare because of the numerous ossified tendons running along the bases of each neural spine almost like spaghetti was stretched across the vertebrae.


Section of dorsal (back) vertebrae before preparation.

Same section (other side) of dorsal vertebrae after preparation. Ossified tendons run along the vertebrae like spaghetti.

The pelvis of Dryosaurus is almost complete and quite impressive now that it has been completely prepared.

A view of the pelvis from above. The tail would start at the back of the pelvis on the left.

Already several problems have surfaced. The rock surrounding several of the tail vertebrae is harder than the bone encased within it. The bone forms thin and delicate processes that I don’t think will survive the removing of the rock around them. We have decided to expose as much of one side as we can then mold and cast the vertebrae with the rock still attached. We will then take the cast and remove the cast rock from around the cast vertebrae and sculpt the processes that are missing. Once the cast vertebrae are sculpted like the real vertebrae, we will make another mold and cast of the finished vertebrae. This process of double molding and casting is time consuming but it will preserve the integrity of the fossil.

Tail vertebrae from the Yale Peabody Museum after partial preparation.

Same tail vertebrae from the other side.

Another problem that has come along is the fact that the YPM fossil material was collected so long ago that the glues and plaster holding the material together is starting to fail. This makes handling and molding the material extremely difficult. The Yale Peabody Museum (YPM) prefers to use reversible glues and materials to consolidate their fossil material. Although this allows changes to be made to the fossils if something is glued wrong or covered up, it also makes the material more fragile. The CMNH also prefers using reversible adhesives and consolidants unless the fossil is to be exhibited for a long period of time. Because the fossil material will be mounted for decades and will undergo all manner of daily wear and tear, it will need to be glued and consolidated with materials that are very durable but not as reversible.

A series of thirty tail vertebrae from the YPM will be used in our mount. At least half of these still need to be partially prepared. A number of limb elements will require a mirror image sculpture to be made. For example-we have the right humerus (upper arm bone) but not the left humerus. Using the right humerus, an exact mirror image will be sculpted for the left side. Dan Pickering, our sculptor, will explain this technique later.

Several tail vertebrae from the Yale Peabody Museum that still require rock to be removed before molding or casting can be done.

Example of mirror image sculpting with the real femur on the right and the sculpted one on the left.

Now that we have received the material from the other institutions, the real project begins. In agreement with the YPM for loaning us their Dryosaurus material, we will make molds of all the material (fossil and sculpted) to render a cast of Dryosaurus that the YPM can exhibit in their museum. This will require us to do much more than we had previously anticipated. Normally we would only make casts of the Dryosaurus fossil material from other institutions. Now we have to mold and cast everything (every Dryosaurus skeletal element-from the head to the tip of the tail).

We were able to supplement our Dryosaurus fossil material with fossil material from the Yale Peabody Museum (YPM) and the American Museum of Natural History (AMNH) to make a composite Dryosaurus skeleton that is 75% complete. Together the Carnegie Museum of Natural History (CMNH) along with the American Museum of Natural History and Yale Peabody Museum has almost all of the Dryosaurus altus fossil material in existence. To complete our Dryosaurus mount, we will have to sculpt or fabricate the remaining 25% that is still missing. The easiest way to do this is to find the elements we are still missing from other dinosaurs closely-related to Dryosaurus and scale the material appropriately to fit our Dryosaurus mount.

Here you can see a skeletal representation of Dryosaurus with all the fossil skeletal elements from CMNH, YPM and AMNH highlighted. The missing elements are left white and will have to be sculpted or acquired from other dinosaurs closely-related to Dryosaurus.

After removing all the Dryosaurus fossil material from the wall mount, we began taking inventory of all our Dryosaurus fossil material from our collections and the material removed from the mount. In total, our Dryosaurus fossil material constitutes about 35-40% of an entire skeleton. This means that we will have to borrow Dryosaurus fossil material from other institutions in order to make our Dryosaurus mount complete.

Here you can see a skeletal representation of Dryosaurus with all the fossil skeletal elements from the wall mount and from our collections highlighted.

Dryosaurus altus will be one of the many dinosaurs exhibited in the renovated dinosaur hall. We have been assigned the task of removing our specimen of Dryosaurus from the wall mount and then making it into a free-standing mount. Unfortunately our Dryosaurus mount is not complete and will require us to use other specimens from other institutions to make a composite skeleton.

Here you can see the skeleton of Dryosaurus altus as a wall mount. A number of things are wrong with the way the skeleton is posed. We now know that dinosaurs did not normally drag their tail on the ground or walk around in a upright kangaroo position. Also, various sculpted elements are poorly made or inaccurately shaped or scaled. All of these problems will be remedied for the new free-standing mount of Dryosaurus to be exhibited in the renovated Carnegie Museum Dinosaur Hall.