How about creating a slab out of air dry clay and then painting it? You
could make the slab very irregular looking like part of a rock. Have the
kids choose local wildlife to paint just like the cave painters would have
done. Notice that you rarely see carnivores painted as the animals they
hunted were very important to humans survival.
Crystal has a great video on the Lascuax caves. I show it to my fourth
graders. We do the paper bag project with chalks and charcoal each year, but
you said you didn 't want to use paper bags. Good luck. JH