[1, 2] stóru grjóti, steini; fyrir ‘massive stones, rock; in their path’: Grjót may well have its common collective sense. The syntactic role of the two dat. references to stone (grjóti) or rock (steini) is not certain, although it is clear that one or both of them must be governed by kastat ‘hurled’ (l. 4). The main possibilities are the following: (a) Fyrir is here taken as an adv. meaning ‘in front, ahead [of them], in [their] path’, while grjóti stóru and steini are in apposition, both governed by kastat (so Kock in Skald and NN). (b) To construe Gær sák stóru grjóti kastat harðliga; hauss gein fyrir steini ‘Yesterday I saw massive stones hurled mightily; a skull gaped open before a rock’ (so also ÍF 28; Hkr 1991) makes good sense, but fyrir would be problematic, since the monosyllabic form fyr would be usual when the prep. is immediately followed by the noun phrase it governs. Only fyr is required in prepositional use in ÞjóðA Magn 13/5, 14/5, 14/7, Frag 1/3, Har 1/3, contrasted with the disyllabic fyrir in adverbial usage in ÞjóðA Lv 3/4 and 9/7. (Konráð Gíslason noted the rarity of fyrir as prep. and considered emending to ginu hausar fyr steinum ‘skulls gaped before rocks’, but drew back from that; Nj 1875-8, II, 855-6.) (b) Fyrir could govern grjóti stóru, in which case the disyllabic form is due to the fact that it does not directly precede that phrase (cf. yfir in st. 4/6), while kastat governs steini, hence sák steini kastat harðliga; hauss gein fyrir stóru grjóti ‘I saw rocks hurled mightily; skulls gaped open before great stones’ (so Finnur Jónsson in Hkr 1893-1901 and Skj B). However, the prose w. o. assumed by this construal is non-obvious at best, and the same problem arises as for (b).