The Prehistoric period begins when the first humans entered the area some 12,000 years ago, and ends with the arrival of the Spanish and written documents in the 1500s. The Historic period refers to the time of written records when the Concho and Colorado River valleys were settled by European colonists and subsequently became part of Spain, Mexico, the Republic of Texas, and finally the United States. Artifacts and Features Archaeologists study the remains left behind by humans during their everyday lives. These remains consist of artifacts and features .
Artifacts are objects made or modified by humans.
Prehistoric artifacts include objects made of stone, bone, and shell. Historic artifacts include pieces of broken pottery, glass, and metal, as well as architectural fragments such as bricks, concrete, window glass, and nails. Knowledge of when such objects were made and utilized allows archaeologists to reconstruct the lives of the people who used these objects and estimate when they lived in the area. An archaeological feature is an artifact which can't be removed intact from the ground. Features include hearths or mortar holes on prehistoric sites and wells and foundations on historic sites.