Digging a site destroys it, so archaeologists are careful to keep good records of where they dig. The squares follow the reference grid for a site, allowing good horizontal and vertical control. It would also be possible to work in triangles, circles, or hexagons, but squares are the easiest to keep track of and map. In the United States most archaeologists are trained in university programs of anthropology. Anthropology is the study of man in all times and in all places.
Archeology is a sub-discipline that uses material remains to study people and cultures of the past.
No and no. It is a common misconception that archaeologists are only interested in Indian history. Archaeologists are interested in the human story through a study of the things they left behind. In North America, that involves both the Indian and the Euro-American cultures. In other parts of the world, archaeologists study the history of the people who lived there.