Why was digging in Pictograph Cave important to all scientists?
As the scientists carefully dug up the artifacts in Pictograph Cave, they made an important discovery. They found that ancient people used the caves during four different time periods. They knew this because each group had left belongings that were eventually covered up by falling dirt and rocks. Scientists from other states could compare the artifacts that they uncovered on their sites to those from Pictograph Cave. Similar artifacts were the same age. This discovery was so important that the United States Government made Pictograph Cave a National Historic Landmark. When artifacts are uncovered, their location relative to each other usually provides more information about a site than do actual shapes of artifacts themselves. Pictograph Cave proved no exception. Workers excavated the caves using a grid system of sections that were exactly 10 feet square. All material removed was sifted, and all artifacts carefully recorded and stored. This painstaking procedure showed researchers that
