DO YOU KNOW THE HISTORY BEHIND THE DIFFERENT COLLORS IN THE LAYORS? I SPENT 3 YEARS STATIONED IN RAPID CITY AND WAS MY PLEASURE TO TAKE A GEOLOGY CLASS WHILE THERE.
EACH DIFFERENT COLORED LAYER REPRESENTS A DIFFERENT TIME FRAME, MEASURED IN MILLIONS OF YEARS, IN WHICH SOUTH DAKOTA WAS COVERED WITH A SEA. EACH TIME, A DIFFERENT LEVEL OF SILT WAS BROUGHT IN THROUGH THE AGES.
COOL HUH?
REGARDS
