In this paper it is argued that there existed, in a certain period of the history of Latin, a floating C-Place node in some lexical items in word-and stem-initial position. Notably, this was involved in the phonological representation of the words written -in an archaising fashion -with initial ngnm. Based on a thorough analysis of the Brepols Corpus (CLCLT-5) it is demonstrated that the diachronic distribution of the prefixed forms of ngnm-initial stems shows restrictions that can only be explained if one assumes a geometric representation involving a floating C-Place node that remained in the place of the original velar stop inherited from Proto-Indo-European. By classical times this floating node was also lost, and thus the possibilities for combining prefixes with original ngnm-initial stems expanded.