.University of arizona .students shovels dirt to be screened of dirt from.the Marana Platform mound looking for.shards and other artifacts from the .mound occupied for 100 years by the HoHoKam.people from 1200 ad to 1300 ad.....in this picture the students are evacuating.a room 40x40 in size, they have divided it up into.four sections and are working one quarter at a time...