At the side of the (newly widened) road in Ballinascorney, I've passed this umpteen times and never recognised it. It's quite hard to spot, but very distinct when you do. From bottom of fosse to top of mound is maybe a foot, and the bank is quite clearly visible too. It's very circular and maybe 8 metres in diameter, though cut into on the side closest to the road. I would call this a disc barrow or a ring barrow (as it is called in Monumental About Prehistoric Dublin by Tom Fourwinds, from whence I got my directions).