To Josh and Pedro, it sounded like a great summer trip: fossil hunting. They would be outside, and the trip would look awesome on college applications. Their parents were okay with the idea - if they stayed within the United States. Both boys liked learning about extinct animals, but for this trip, Josh wanted to search for the very first animals. Pedro, on the other hand, loved his pet parakeet, so he wanted to look for the ancestors of birds. But where could they find these fossils . . . and were any sites close enough to satisfy their parents?

Next, they needed to figure out in which periods their target animals lived. Then, they needed to figure out where they could find rocks of the appropriate ages. In this chapter, look for clues to the geologic time periods the boys' target animals might have lived in and where the two boys might expect to find their fossils. Then, solve the mystery.