Provide digging tools and have the children dig for pretend dinosaur bones.
Brushes can add to the drama.
Pretend role play by talking about how we must be careful when we find a bone, and show them how to brush the sand from it before removing it. Allow them to help you make a batch of Plaster of Paris and pour it into their trays. While the mixture is still wet, have children press tiny stones, leaves, bones, seashells, sticks, and other natural objects into it to make imprints, then remove the objects. Make green and gray playdoh. Still, I wasn't sure they'd like this song that a co-worker passed on to me.