In 1824, the British Parliament authorized the mapping of all of Ireland at a scale of six inches to one mile, an unprecedented undertaking. At this scale, every field, every building would be rendered in its exact shape and dimensions. If Britain could not reduce Ireland to passivity in life, then it would do it on paper.
Throughout the 19th century and well into the 20th, the standard elevation (bench) mark for surveyors in Ireland was the "crow's foot," a horizontal line with three radiating marks below, chiseled by masons into stone buildings, bridge abutments, piers and walls. Here is one from the wall in front of the primary school in our village. Click to enlarge.
The crow's foot became part of the folklore of Ireland, mysterious, enigmatic, a kind of magical talisman. They could pop up anywhere. We used to see one on a flat boulder on the old green military road up the side of Mount Brandon, out in the middle of nowhere. For some years now it seems to have disappeared, perhaps tumbled away in a flash flood.
In this day of aerial and satellite imagery and GPS, the marks are no longer used or maintained by the Irish mapping agency, and with development, the widening of roads, and the replacement of bridges and outbuildings, the crows' feet are fast disappearing. I know of several in our village that have vanished. Here is one in a wall just down the road that is about to disappear beneath brush and moss.
A great cultural loss, I think, equivalent to the gradual eradication of cross-inscribed stones, ring forts and holy wells from an even earlier era. Those archeological artifacts are, of course, catalogued and more-or-less protected. I'm rather surprised that some informal web-based community hasn't organized to map the locations of remaining crows' feet and track their slow extinction -- or at least I didn't find such a group on the web.
I'll do my bit. I'll take my strimmer down the road and whack out the one pictured above from encroaching nature. I like seeing it there on my walks, a reminder that once long ago a team of surveyors came this way, with their levels, theodolites, chains, and field books, bringing exact scientific description to a landscape permeated with fairy spirit.