 He discovered many prehistoric sites, although he is best known for his discovery of the Beaghmore stone circles, and developed the theory that they were an ancient lunar observatory.This theory was expressed in his poem, "The Beaghmore Stone Circles".Ceremonial occasions they often had there,
They knew every day, aye, and week in the year,
For fifty-two weeks they had stones in a ring,
Thirteen in a line for the time the call Spring.