As her mother cheered from the sideline of a soccer game last fall in Bend, 7-year-old Naomi Vaughan went off to play in the nearby woods     1    (surround) the soccer fields. Naomi passed the time digging a hole in the dirt. After a while, something shiny caught her eye and she lifted it out of the soil     2    (show) her mother. She called it her ＂Moana rock,＂ because it reminded     3    (she) of the spiral-shaped amulet (护身符) from the animated Disney movie.

Her mother, Melissa Vaughan, examined the relic and knew it wasn’t just some     4    (dust) rock. ＂I can’t believe you just found that,＂she told her daughter. ＂It could be millions of years old.＂    5     Naomi found was     6     ancient fossil called an ammonite(菊石), an extinct marine creature     7     last existed more than 65 million years ago.

Experts say ammonites     8     (be) not naturally found in Bend, Ore., but are common to the east near Mitchell, Ore., more than 80 miles away. How this ammonite wound up in Bend is a mystery.

Greg Retallack, an expert in ammonites,     9    (believe) the fossil originated from the Bernard Formation of Bernard Ranch near the abandoned eastern Oregon town of Suplee — about 112 miles east of Bend. Because experts don’t know     10    exact) where it came from, it is scientifically worthless.