How to Make a Fossil

     BECOMING A FOSSIL ISN'T EASY. MOST PLANT AND ANIMAL REMNANTS GET
DESTROYED BY THE ELEMENTS OR EATEN BY SCAVENGERS LONG BEFORE THEY HAVE
THE CHANCE TO TURN INTO ROCK.  MANY PALEONTOLOGISTS SUSPECT THAT THE
FOSSILS WE FIND TODAY MUST HAVE BEEN BURIED VERY QUICKLY TO HAVE BEEN SO
WELL PRESERVED--LIKE THE ANIMAL BONES THAT WERE SHELTERED FROM
DESTRUCTION IN TARPITS. BUT NO ONE IS SURE OF ALL THE CONDITIONS CONDUCIVE
FOR FOSSILS, SAYS PALEONTOLOGIST SALLY WALKER AT THE UNIVERSITY OF
GEORGIA.

     Walker: "you have to know what kind of places you want to get buried, basically the temperature
has to be just right, the oxygen concentration has to be just right, the lack of toher organisms like worms,
say, burrowing. . . you can't have a lot of those."
     WALKER IS STUDYING JUST WHAT MAKES A GOOD FOSSIL IN DEEP WATER. HER
GROUP, LED BY ERIC POWELL AT TEXAS A&M UNIVERSITY, WENT DOWN IN
SUBMARINES AND DROPPED BAGS OF POTENTIAL FOSSILS--THINGS LIKE CRAB SHELLS
AND SEA URCHINS AND WOOD.  WITHIN A YEAR, THE BAGS WERE ALL QUICKLY BURIED
ON THE OCEAN FLOOR.  BUT JUST BEING BURIED WASN'T ENOUGH TO PROTECT THE
SAMPLES.  WHEN WALKER AND HER COLLEAGUES WENT BACK TO CHECK ON THEM,
THOSE IN SHALLOWER WATER, SAY 200 FEET, DIDN'T SEEM TO FARE AS WELL AS THE
DEEP ONES.

     Walker: "they had little pits on them, with some green algae. they were encrusted with . . . worms
all over. . .they were getting inhabited completely by organisms. . .and I must add. . .at 800 feet . . .they
looked absolutely spectacular."

     THIS COULD BE DUE TO A CHANGE IN CHEMICALS OR A CHANGE IN THE NUMBER
OF ORGANISMS AROUND TO ATTACK THE SHELLS, SINCE THERE TENDS TO BE LESS
MARINE LIFE THE DEEPER YOU GO.  DETERMING WHICH SHELLS GET DESTROYED IS AS
IMPORTANT TO THE GROUP AS DETERMINING WHICH GET FOSSILIZED, SO THEY CAN
MONITOR HOW MINERALS FROM THE SHELLS GET RECYCLED. THE GROUP HOPES TO
CHECK ON THEIR SAMPLES ONCE A YEAR OVER TEN YEARS TO SEE IF THEY NOTICE
OTHER GROWING TRENDS IN A BABY FOSSIL'S LIFE.