Very nice day to be outside, in the Montana badlands, out at a dig site, working under a nice shade canopy on a beautiful summer day. We finished pedestaling the second ilium (hip bone) and then wrapped it up in a plaster field jacket, getting it ready to transport out.
Without the field jacket, if you tried to ease the bone up and just pick it up in your hands it would crumble, coming apart at each broken seam, literally going to pieces and spewing off tiny pieces of bone here and there. No can do – must jacket each piece to preserve it in its current shape and form then slowly expose it back in the workshop under a controlled environment where we can carefully “reconstruct” it. How do we stick the separate pieces back together?; well, with dino glue, what else, silly. Cryno-aculate glues (similar to super-glue) come in different viscosities, from really thin, that will easily flow into tiny cracks, to very thick, for helping to bring together pieces with significant cracks.
We then removed matrix from all around the “comcloberation” (that’s scientific jargon for “all stuck together”) of three bones we’re going to try to remove as one, in one large field jacket. The big thigh bone and two bones that make up the lower leg, the shin, are folded back on one another and would likely be greatly harmed in trying to separate them here at the dig site. This is a really clear example of pedestaling a bone to preparer for jacketing.
Right before you install the plaster and burlap straps it appears that the bone is “up in the air” on a pedestal (or 2) of dirt. It’s not; it’s that we’ve removed all the surrounding soils (matrix) so we can get “purchase” on the sides of the bone with the plaster, to hold the bottom of the bone in place once the plaster gardens and we’re ready to roll the specimen over to remove it from the site. This “roll” is critical; critical that the plaster & burlap had hardened and we’ve applied enough of it, in the right places and directions and that it’s gripping the soil under the bone so that when we free it from its pedestal and roll it over, the soil on the then bottom holds in place keeping bone fragments in place. Nothing worse than in the middle of rolling over a large bone to hear and feel that terrible sensation of the matrix and bone bits just cascading out of the open bottom in the middle of rolling the piece over! We get the plaster jacket to “grab hold” of the edges, under the bone, to prevent it from coming apart during the roll.
You’ll see in the photos of the pedestaling of this group of 3 bones that we’ve also tunneled through in a couple of places; there we’ll actually wrap the burlap strips completely around the bones. This greatly helps insure that these long bones stay together, as one, when we roll them over. Also removed matrix from each end of the bones so we can take the long burlap strips soaked in plaster around the heads of the bones; this also helps solidify the piece. Lastly, we’ll plaster in place, with the jacket, some wood or metal to act as a splint and help stiffen the whole thing. Quite a process.
I cleaned up the site in time to cut out, get back to camp and clean up for nice meal with the ranch owners. We went to “The Gem,” a rehabbed old movie theater that’s converted into a brew pub and fine restaurant. Wonderful food, beer and conversation with the Beck’s and their son, Nathan and his wife Erika (and their soon to arrive 1st born little fellow who was with them but not made his first appearance yet).