They had stopped to rest beneath a finger-post where four roads met…
From Master Humphrey’s clock vol.1 , by Charles Dickens, illustrated by George Cattermole and Hablot Knight Browne. London, 1840. Via the OBI Scrapbook Blog.
The OED lists usages going back to the late 18th-century and notes that a finger-post typically had arms which terminated in the shape of a finger.
Searching the term, I came across this connection to the word "crucial":
crucial - 1706, from Fr. crucial... from L. crux (gen. crucis) "cross." The meaning "decisive, critical" is extended from a logical term, Instantias Crucis, adopted by Francis Bacon (1620); the notion is of cross fingerboard signposts at forking roads, thus a requirement to choose.You learn something every day.