Traditionally in the U.S., archaeology is regarded as a major subfield of anthropology. Bowdoin seems to lack this major track, and instead appears to offer a handful of courses in archaeology as a way of supplementing their classics and art history departments. The College combines its anthropology with sociology to form one department.
With respect to the colleges mentioned in #3, all offer an array of archaeology courses within dedicated anthropology departments. Hamilton is curricularly balanced between the sciences and math, the humanities and fine arts, and the social sciences. Bryn Mawr, with its bi-college relationship with Haverford, offers curricular breadth as well. Beloit I recommended primarily on the strength of what I know about its anthropology department, but the rest of the college seems worth researching as well.