Posted by: Kirsten | Tuesday, 19 August 2008

Squamosal Extraction 101: Try this at home!

Step 1: Find that dinosaur bone
At home, try this yourself using a ham or turkey bone buried in a large tray of dirt.  Add water then allow to completely dry in the sun for several days before attempting to dig. If the bone is breakable, go ahead and break and snap it into several pieces and reassemble before burying it.  This might go over even better if you have a real (non-farm) animal bone like a deer leg bone, cow vertebrae, or some piece of bone you collected from the beach several summers ago.  Soil with lots of clay will harden better and more accurately reflect the difficulty of extracting a fossil from rock.

Lookie here, I found a dinosaur!

Lookie here, I found a dinosaur!

Step 2: Carefully remove all surrounding dirt and rock
Give the kids some safe tools if they’re small, or go for the real tools (X-acto knives and other precision tools) if you can trust them not to kill themselves.

The most tiring and paintaking step!

The most tiring and painstaking step!

Step 3: Cover with aluminum foil
Here’s one step where you can use the real thing… although you’ll need a lot less of it.

Make that wrap STS (smooth, tight, and sexy!)

According to Tyler Lyson: Make that wrap "STS" (smooth, tight, and sexy!)

Step 4: Add wood or similar for support
For the at-home simulated fossil dig, popsicle sticks are good here, or use your imagination and find anything that lends some support whether the bone needs it or not.  Pretend the bone is extremely fragile, even if it isn’t.

Brace the fossil lengthwise with a board before adding water to the plaster mix

Step 5: Cover with plaster jacket.  Allow to harden.
At home, Plaster of Paris or other similar stuff should do the trick.  Instead of burlap strips, use sturdy paper towels like Bounty or Brawny that will soak up the plaster but not fall apart.  Be sure to cut them into very thin strips so it takes several to cover the bone… don’t let the kids cover everything with one fat strip — that’s cheating!

Gotta be quick about it... that plaster hardens fast!

Step 6: Carefully flip entire jacket over and remove excess dirt, mud, and rock.
Once everything has dried and hardened, use popsicle sticks to slide under your bone jacket and carefully flip it over.  Carefully remove as much of the extra dirt as you can from the plaster jacket and your fossil is now ready to transport — to the kids’ bedroom (the lab) for further prep work!

For large fossils, removing the excess dirt and rock can make everything hundreds of pounds lighter

Step 7: Haul squamosal back to the lab for preparation.
This is the part where you never see the chicken bone again and continue to wonder if it’s going to show up in the dryer lint trap any day now. 

Two poles, a burlap sling, and lots of muscle to haul everything to the nearest vehicle

“What’s a squamosal?” you are probably still wondering by now.  Well, on a Triceratops, it’s the side parts of the huge frill that protects its neck from wandering T-Rex teeth, and perhaps other Triceratops horns. There’s even a squamosal bone on the human skull, but I’ll let you look that up on your own.  Happy fossil collecting.

Parke Diem!
— Jon

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