A Long Way From Wemyss

Recently I learned that my Scottish forebears, the Bealls, were exclusively from one village in Fife. Wemyss, the village in question, is pronounced "Weems" and derives from the Scots Gaelic noun uaimh, which means "cave". There are certainly many caves near Wemyss, some of which were inhabited in the Neolithic Age and feature typically frank drawings. My ancestors, the Bealls, derive their surname from the Scots Gaelic noun beul or beal - the "extra" a or u indicates a broad, rather than slender, final consonant. This feature reminds me of a comment of Tolkien regarding Elvish spelling of English, namely that an elf such as Legolas would spell "bell" as "beoll". beul means "mouth", either that of a river or a person, and as an adjective, may refer to physical location or rhetorical skill. It seems to me there is a third option: in a place that is named after caves, why couldn't beul refer to the mouth of the caves instead? Since one regional cave in particular is famous for its rock drawings, the family that lived at the mouth of the cave would have a unique appellation.