In this paper we present a part of corpus-driven semantico-grammatical ontological description of Russian prepositional constructions. The main problem of a prepositional ontology is its inner controversy because the ontological structure presupposes logical analysis of concepts, however, prepositions are usually interpreted as non-lexical grammatical language elements. In our understanding, this is an ontology of lexico-grammatical relations that are implemented in prepositional constructions. We demonstrate the ontological structure for semantic rubrics of temporal and locative syntaxemes extracted through the elaborated technique for processing corpus statistics of prepositional constructions in modern Russian texts. Common and contrastive traits between this two topmost semantic domains are shown.