That is precisely the situation at this site on flat ground straddling the townlands of Castlelloyd and Garryduff in County Limerick. The Ordnance Survey six-inch map of 1840 records no trace of it. Neither does the more detailed twenty-five-inch edition of 1897. As far as the cartographic record is concerned, this patch of land has always been featureless grazing. The aerial camera told a different story.

The system came to light through the Bruff aerial photographic survey, which catalogued it as a relic field system under reference Bruff 20.5. What the survey photographs revealed, and what later orthoimages from the Ordnance Survey Ireland series taken between 2005 and 2012, and Digital Globe images from 2011 to 2013, have since confirmed, is a coherent layout of four parallel field boundaries running on a NE-SW orientation across an area roughly 250 metres north to south and 200 metres east to west. The system sits in close proximity to two enclosures already recorded in the Sites and Monuments Register. At the southern end of the plot there is evidence of spade cultivation thought to be contemporary with the field boundaries themselves. Spade cultivation, worked by hand rather than plough, was common in Ireland particularly in the post-medieval and early modern periods and often left faint but readable impressions in the subsoil that aerial photography can pick up long after the ground has been returned to pasture. The record was compiled by Edmond O'Donovan and uploaded in September 2020.

Because the features are crop marks and soil marks visible from altitude rather than upstanding earthworks, there is little to see at ground level. The site is on private agricultural land, and any visit would require landowner permission. The most accessible way to examine the layout is through Google Earth, where an orthoimage dated 18 November 2018 shows the boundaries clearly. Those interested in the broader landscape context can cross-reference the two nearby enclosures on the National Monuments Service database to get a sense of how the field system relates to earlier activity in the area.