People lived in many parts of the Old World by then but had not yet reached Australia or the Americas. The bulk of the human ...

The new trilobite fossils are Cambrian in age (around 509 million years old) and preserved ... with the volcanic ash quickly molding and cementing the animals in place. This entombment must ...

Thank goodness for the irrepressible urge of humans (and other animals ... thousands of years old. But this trail, some 80 feet long and preserved in cementlike volcanic ash, had been made ...