Drystone walls. A drystone wall is a wall that has been built using stones only, without the use of any mortar or concrete. A well-built dry-stone wall has the advantage over a mortared wall in that it adapts perfectly to instability and other changes in its environment. Drystone walls are as old as the times that man settled into sedentary life. The walled-in, arable fields here are on Inishmore, one of the Aran Islands off the western Irish coast.