A hollow way pursuing a somewhat meandering course for c.258m N-S across Cefn Eglwysilan.
The feature is 3.0-4.0m across at the top, from 1.5-2.0 at the base, and is c.1.0m deep, fading rapidly at its N & S ends.

(source Os495card; ST19SW11)
J.Wiles 07.02.03