Natalie picked up the fragment and began to examine it. With the help of her small magnifying glass she scrutinized it more closely before dropping it into her specimen satchel. She called out to the other two members of her team: “John! Mike! Anything yet?”

John looked at Mike, who was busily digging below the rocky surface. “Mike?” Mike shook his head and continued digging. “Nothing, Natalie. And, you?”

Pushing her glasses back into position on ...