Crop marks like this form when buried features, walls, ditches, or filled pits, affect the moisture and nutrients available to growing plants, producing differences in colour or height that only become apparent from the air, or in this case, from satellite imagery. The enclosure at Common was picked out precisely this way, identified from Bing aerial photography in early 2015 by researcher Christine Baker.

What makes the site particularly interesting is its relationship to the landscape around it. The circular form appears to predate a field boundary that once marked both the western limit of a place called Kit's Green and the townland boundary between Common and Corrstown. In other words, whoever made this enclosure was working in a landscape that did not yet have those boundaries, suggesting considerable age, though the notes stop short of assigning a specific period. That field boundary has since been removed entirely, meaning the enclosure now sits in a field stripped of the very feature that helped define its relative chronology. There is a further tantalising possibility: the first edition Ordnance Survey map, produced in Ireland during the 1830s and 1840s, marks what it cautiously calls the "supposed site of old Fort or Burying Ground" in this area. Whether that annotation refers to the same circular feature is uncertain, but the alignment between the two is suggestive. A circular enclosure of this size could represent a ringfort, a type of enclosed farmstead common across early medieval Ireland, or potentially something older still.

The site has no public monument marker and no formal access point, and because it exists only as a subsurface trace there is nothing to see at ground level under ordinary conditions. The crop mark itself would only be visible from the air, and then only at the right time of year when differential crop growth is at its most pronounced, typically during a dry summer. The surrounding field boundaries that once provided navigational context have been removed, making precise location on the ground more reliant on map coordinates than on any visible landmark. For those with an interest in landscape archaeology rather than upstanding ruins, it represents the kind of site that quietly rewards attention to old maps and overhead imagery rather than a visit in the conventional sense.