Archaeology, as I understand it, is akin neither to geology (the analysis of buried layers) nor to genealogy (as the description of beginnings and their sequels), it is the analysis of discourse in its modality as an archive.
DE48, translated as “On the Ways of Writing History” Essential Foucault, II Aesthetics, Method, and Epistemology, 279-295 at 289-90, trans. modified.
This seems to me to be a very useful insight into Foucault’s archaeology. What does it mean? Here the archive is not just the literal archive in depositories and libraries, but treating discourse as that deemed worthy of rising to the required level of affect. If you like, the archive as assemblage, but only if this is understood as something geographically and historically variable, contested etc. In geography, we might cite David Livingstone’s The Geographical Tradition. Regimes of truth we might also say, as well as the technologies, implicit and explicit, for verifying such truths.
Remember that Foucault wants to distinguish himself from a history of ideas. This might be nothing more than an attitude or way of looking, and presents epistemic difficulties in accessing discursive and non-discursive affect, but one which when dealing with an archive one can examine on its own terms, even if those terms are around “minor” figures.