Two of these stones lie within the river itself, one sits beside its bank, and a fourth stands outside what was once a caretaker's house. It is an odd distribution, strung along the water as though the stones drifted there, or were never quite gathered into a single place of significance.

Bullauns are among the more enigmatic features of early Irish ecclesiastical sites. They are roughly circular depressions, carved or worn into granite or other hard stone, and are found at monastic settlements across Ireland, though their precise function remains debated. Some scholars associate them with grinding or processing, others with ritual use, and many sites have accumulated folklore about their water holding curative properties. The Sevenchurches area, the old name for the Glendalough monastic complex and its surrounding valley, was a place of considerable ecclesiastical activity from the sixth century onward, and the presence of bullauns here fits a pattern seen at similar sites. One of the Glendasan stones was recorded by Healy in 1972 as a boulder measuring roughly 0.9 metres by 0.5 metres by 0.4 metres, containing two basins of slightly different diameters and a depth of around fourteen centimetres, with what appears to be a partial third basin beginning to form, or perhaps wearing away, in the same stone.

The river setting of two of the stones adds a particular curiosity. Whether they were originally positioned at the water's edge and shifted over time, or were placed deliberately near a water source, is not recorded. The fourth stone, near the caretaker's house, suggests that at some point someone moved at least one bullaun, or that the site's boundary shifted around it. Visitors to the Glendalough valley who walk the Glendasan route, rather than heading directly for the round tower and cathedral, are more likely to encounter this quieter cluster of early stonework.