The site featured at least four simple cup marks; circular depressions hammered into the stone surface that are characteristic of Bronze Age carvings found throughout Ireland and Britain. Most intriguingly, one of these cups was surrounded by a complete or possibly gapped ring, with what may have been a tail extending eastward, though centuries of weathering made this detail difficult to confirm. An additional doubtful cup mark was partially encircled by an irregular groove of uncertain origin, adding to the mystery of who created these markings and for what purpose.

The carvings were documented in detail by researcher Van Hoek in 1987, who noted that the rock surface sloped nine degrees to the south southwest. These ancient markings, likely created between 2500 and 500 BCE, represented part of Ireland's extensive tradition of cup and ring art; abstract symbols whose meaning remains debated amongst archaeologists. Some theories suggest they served astronomical purposes, marked territorial boundaries, or held ritual significance for the communities who created them.

Tragically, by 1988, just a year after Van Hoek's detailed survey, the entire rock outcrop had been destroyed by dynamite blasting during quarrying operations. This loss represents one of many instances where Ireland's prehistoric heritage has fallen victim to industrial development, making Van Hoek's documentation all the more valuable as the only surviving record of these ancient carvings. The destruction of the Magheranaul rock art serves as a sobering reminder of how fragile and irreplaceable these connections to our distant past truly are.