As in any other profession, fields of specialization exist in archaeology. For example, paleoanthropologist Donald Johanson searches in Africa for the fossilized bones of our earliest ancestors. Prehistoric archaeologist Dennis Stanford looks for traces of the earliest Americans. Physical anthropologist Douglas Owsley helps to identify the bones of soldiers killed at the Battle of Antietam in 1862. Conservators like Betty Seifert use their knowledge of chemistry to preserve the artifacts recovered from sites, so that these objects will be available for future study.
Historical archaeology is a specialized subdiscipline within the field of archaeology.
Historical archaeologists study not only artifacts and sites, but also the documents written about the people and places they are studying. Urban archaeologist Pamela Cressey excavates the shops and houses of 19th-century Alexandria, Virginia. Doug Scott examines the Little Bighorn Battlefield in Montana where the Sioux and Cheyenne defeated Custer. Underwater archaeologist George Bass dives on ancient shipwrecks in the Mediterranean. And all of them depend on research historians like Amy Friedlander and Victor Geraci to find old documents and maps to help explain the artifacts and features which they find in the ground.