This paper has as its aim to connect two seemingly disparate phenomena: the structure of Basque adpositional phrases and the synchretisms arising in plural DPs between ergative and absolutive arguments in some of the dialects of Basque. This synchretism, which can be found in western and central dialects of Basque, resolves in favour of absolutive marking, and has been taken to be the product of relatively shallow historical morphophonological processes. If the approach held here stands a reasonable chance, there may be a different way of looking at those synchretisms, by putting them in the context of diachronic processes related to the expansion of number morphology, and by capitalizing on the incompatibility of number with a particular kind of syntactic object: the so called axial part (Jackendoff, 1996), an integral part of locative constructions cross-linguistically, if recent work on the structure of those constructions is on the right track (see Kayne, 2005; Svenonius, 2006; Pantcheva, 2011, among many others).