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Backstage Pass to North Dakota History

This blog takes you behind the scenes of the State Historical Society of North Dakota. Get a glimpse at a day-in-the-life of the staff, volunteers, and partners who make it all possible. Discover what it takes to preserve North Dakota’s natural and cultural history. We encourage dialogue, questions, and comments!

Adventures in Archaeology Collections: What Have I Been Doing?

So many projects have been going on all at once that it was too hard to pick just one for the blog. So instead, let’s look at a variety of projects.

One of the projects that I am working on involves processing (labeling, rebagging, photographing as needed, and cataloging) a federally-owned archaeology collection stored here.

Compuer screen showing work in progress.

Work in progress.

This project involves many different sites. It also includes many types of objects--ranging from historic artifacts like glass bottles to bone tools, flaking debris, and projectile points.

Projectile points

Projectile points from the U.S. Forest Service collections (2012A.166.13, 2012A.166.7, and 2012A.116.1)

We are also still working on the cataloging project for artifacts from Like-A-Fishhook village (32ML2).  My favorite object that we have seen recently is probably this little toy canoe.

Metal toy canoe

Left: Metal toy canoe from Like-A-Fishhook village, a view from the top (12003.1719).
Right: Metal toy canoe from Like-A-Fishhook village, a view from the side (12003.1719).

It is so perfectly shaped. We also recently found a dragon! Well, a metal dragon, at any rate. It is a sideplate from a gun. Another dragon sideplate can be seen on a percussion rifle on display in the Innovation Gallery: Early Peoples at the State Museum.

Metal dragon side plate from gun and .625 caliber Northwest trade gun

Left: A metal dragon side plate from a gun from Like-A-Fishhook village (12003.1908).
Right: A .625 caliber Northwest trade gun made by Isaac Hollis & Sons with a dragon sideplate on display at the State Museum (1982.93).

My supervisor and I also made a poster for a national archaeology conference this past month.  The conference was too far away to attend in person (it was in Orlando), but at least the poster could go to sunny Florida! It was for a session that gave museums an opportunity to share what kind of collections they have available for study. Archaeology collections are meant to be researched, so this was a great opportunity to share with students and archaeologists what North Dakota has to offer. North Dakota really does have amazing archaeology, so it was fun to find pictures of objects for the poster—from Paleoindian projectiles to Woodland pottery to seeds from village sites to gun parts and glass beads from trading and military forts. A lot of work from many people went into this poster. We used photos of artifacts from the Like-A-Fishhook project as well as photos taken by volunteer David Nix (see Wendi’s blog about Dave and his work at http://blog.statemuseum.nd.gov/blog/mission-possible).  We also coordinated with Brian Austin who works on graphic design for the agency—he finalized and printed the final product for us.

Society for American Archaeology conference poster

A small preview of what our poster for the Society for American Archaeology conference looked like.

Speaking of researchers, it has been fun having a researcher working in the archaeology lab for a few weeks. This researcher is an archaeologist who is examining historic bottles from Fort Rice (32MO102) as part of her master’s thesis.

Studying glass bottles

A researcher studying glass bottles from Fort Rice.

We have a sizeable collection of glass and ceramic bottles and bottle fragments from this site. It will be exciting to see what her final project looks like and interesting to learn more about life at Fort Rice.

The Good Kind of Mold…

Mold in paleontology can mean two things. The first (bad kind) happens when you get water trapped in your field jackets (plastered specimens), it sits for ages, and grows a nice layer of Becky-breathing-impairing mold. The second (good kind) is when we need to make a copy of a fossil. Not just any copy, but an exact copy. This could be because a fossil is one-of-a-kind, and we need to show it to other researchers without fear of damaging the original. Or maybe it’s a really neat specimen we want to give away as a souvenir or include as a hands-on demonstration, allowing people to touch the copy.

A mold could be a simple one-sided “dump” mold, where only half of a fossil is copied. This is good for a display mount, perhaps a nice shelf specimen, or giveaways to kids. If the whole fossil is needed, we could need a two-, three-, five-, or even ten-sided mold (depending on the complexity of the fossil). No matter what size mold is created, we make sure the fossil can take the stress. Generally a very thin sealer is put on the fossil to make sure the silicone (our mold material of choice) doesn’t sneak into cracks. Then, we figure out where the pour spout will be and any vents. Anything projecting to the side above the spout or vents can trap air bubbles – so we make sure everything leads up and out. In metal casting, this is called your “sprue” system.

Walls keep the silicone in a mold while it sets. Some people use wood or clay – We use LEGOs! They can make any shape, the clay doesn’t stick to them, the silicone doesn’t stick to them, plaster doesn’t stick to them – they’re perfect to use and reuse. If you notice an odd brick pattern on the sides of all my molds, that’s why.

Sometimes part of the fossil being molded will be embedded in clay (sulfur-free, or my silicone won’t set). As the clay is sculpted around the fossil, I have to imagine it as future silicone. No undercuts or thin spots, or else the silicone will be very difficult to remove and put back together again. The initial silicone is poured on top of the clay/fossil combo and left to cure. Once cured, a mother-mold may be added – this is a stiff backing, which could be plaster or fiberglass to add support later. The mold is flipped over, the clay removed, and a release agent placed on the now-visible silicone we just let cure. Silicone likes to stick to itself, so we need to put a thin barrier in place. Vaseline works great and is inexpensive. We repeat the silicone/mother mold process on the other side, or sides, depending on how many pieces a mold needs to be. Ta da! After everything is cured, the fossil is removed, and the mold is ready to go!

Multi-fossil mold

Multi-fossil mold, to reduce the amount of LEGOs used. Clay backing is visible.

Clay backing removed

Clay backing has been removed, and the first pour (opposite side) of silicone can be seen surrounding the fossil. Clay pour-spout and vent (bottom) left in during the second silicone pour.

Silicone poured over fossils

A thin coat of silicone poured over fossils, and then a thicker coat. This helps to reduce any bubbles our vacuum chamber misses.

Small mother mold

A small mother mold consisting of plaster and cheesecloth helps add rigidity to the end mold. The LEGOs and fossil will be removed next, when the mold is split apart.