Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Volturnus, i, v. Vulturnus.
2. Vultur (Volt-), ŭris, m., a mountain in Apulia, near Venusia, now Monle Vulture, Hor. C. 3, 4, 9; Luc. 9, 185.
Hence, Vulturnus (Volt-), a, um, adj., of or belonging to Vultur: ventus, a southeastby-one-third-south wind, Plin. 2, 47, 46, § 119; Sen. Q. N. 5, 16, 3; Col. 5, 5, 15; 11, 2, 65; Gell. 2, 22, 11; App. de Mundo, p. 63, 14.
1. Vulturnus (Volt-), i, m., a river in Campania, the mod. Volturno, Liv. 8, 11; Verg. A. 7, 729 al.
Hence, Vulturnus (Volt-), a, um, adj., of or belonging to the Vulturnus, Vulturnian: vada, Sil. 12, 521: amnis, Plin. 36, 26, 66, § 194: oppidum, id. 3, 5, 9, § 61.