The big activity for our dinosaur day is always a fossil dig. This is a more advanced version of the basic fossil dig activity where your kids will need to extract fossils from a rock matrix rather than sift them from dirt. Pick a spot in you garden or yard that you don't mind digging up. I usually reserve someplace where I know I'm going to have to reseed/patch or a spot in the garden I'm going to want to till and replant. This activity takes more patience so it isn't always best for the younger ones - we spent 4 hours excavating. It gives your kids a bit more of an appreciation for how painstaking fossil excavation work can be without being so difficult that it loses their interest.
What you'll need
  • Fossil matrix - see instructions for creating a matrix.
  • Tools
    • Handheld shovels
    • Hammer(s)
    • Chissel/flat-head screw driver
    • Wire brushes
    • Soft brushes
    • Picks/dental tools
    • Spray bottle
    • Magnifying glass(es)
    • See tools buying guide for suggestions.
  • small notebooks and pencils
  • baggies or compartmentalized box to store fossil finds.
  • and outdoor surface/table you can move to the dig site. I used some boards across some saw horses. Don't bring out your kitchen table, it won't lead to anything good.
  • (optional) Canopy
  • (optional) Dig site sign  
Picture
Carefully scraping away rock from an exposed fossil.
Setting up
Set up when the kinds aren't watching. I usually do it at night after they've gone to bed. It is a bit of a pain, especially if it is dark, but having them wake up to a prepared dig site adds to the excitement.
  • Find a spot in your yard or garden that you are okay digging up.Dig it up just enough to accommodate your fossil matrix rocks.
  • Cover the rock matrix lightly with dirt.
  • If you have some kind of canopy, set it up on or near the prepared dig site. The canopy, if you choose to use one, has a few purposes: 1 - it ads to the authentic feel but transforming your yard into a more official 'site'. 2 - if it is sunny ... shade!!! 3 - shade! 4 - shade!
  • Set up your working surface under the canopy or near the dig site. 
  • Lay out any tools you have on the surface.
Picture
The work site. Canopy, work surface, tools, and dig site (small dirt patch in back).
The dig
  • Tell the kids what they are about to embark upon - a fossil dig. They will be responsible for finding, identifying and cataloging fossils. Give them a sense of responsibility - THEY will be responsible for doing the work. THEY need to identify what they find. THEY get to keep the fossils!
  • Find the matrix. Using small shovels, uncover dirt from the prepared fossil matrix. 
    • Either dig up the entire rock(s) and move them to the work area or leave it in the ground and work on it where it is.
    • We moved it to the work surface, placing it in the foil pans used to make the matrix. This was an easier surface to work on than crouched on the ground and the pans helped control the mess.
  • Extract. Now its time to extract the fossils from the matrix. They'll be working with a rock-like substance, though not has hard as rock
    • Use a hammer and chisel (or flat head screwdriver) and chip large chunks of "rock" away from the fossils. If buried the fossils deep, use the hammer and chisel to break up the matrix to find the fossil.  
    • Once a fossil is exposed, use picks/dental tools to scrape away the "rock" from the fossil.
    • Once excavated, use fine picks to scrape the dust, dirty, and remaining matrix from the fossil.
    • Use a spray bottle and sponges to was off the remaining fine particles.
  • Identify. They've found the fossils...now figure out what's what.
    • Rather than finding all the fossils at once and then identifying them in bulk, I suggest identifying them as they are found - it breaks up the digging into smaller chunks and holds their attention longer.
    • Using their notebooks, have them make a small sketch of the fossil and write down the grid location where they found it.
    • Use a simple fossil identification guide (often included when you buy fossils) or a book, write down the name of the animal the fossil came from.
    • Store each fossil in a compartment in a box, such as a simple tackle box. Make a label and put it with each fossil.
Picture
Chipping away at the fossil matrix to expose potential treasures.
Picture
Using dental tools to carefully expose and extract a magalodon tooth.
Picture
Labeling and bagging fossil finds