The book of Genesis preserves two different etiologies—origin stories—for the naming of the boundary marker set up to ratify the covenant-treaty made between Jacob (Israel) and Laban (Aram). Presumably they were originally from two different oral traditions that were both preserved at a later time.
In one version, it was the mound of stones (gal), which served as the symbol of the covenant between, not only Jacob and Laban, but remembering that these names are eponymous, between Israel and Aram. It was a border marker between the two countries—namely Gilead.
Yet a variant tradition also claims that it was a stone slab or stela (masheba) that served to symbolize the treaty. Eventually msbh was replaced by msph, that is Mizpah.
Once again, these ancient traditions actually reflect the territorial border between Israel and Aram in the 9th-8th centuries BC, and thus tell us more about their 8th– 7th centuries BC authors than the history of some archaic past. In fact, the former story serves to legitimate the Israelite ownership of Gilead as the Arameans withdrew from the region in the early 8th century (see also #55-56).