11.   Treasure hunters once wandered for days, even weeks, trying to identify specific geological features for orientation.

12.   When possible, his structures, like Fallingwater in Mill Run, Pa., were carefully sited to take advantage of dramatic geological features and natural vistas.

13.   The two sites of the shadow government make use of local geological features to render them highly secure, the Post said.

14.   They will attempt to locate old border markers and study geological features as well as social and technical issues linked to border delineation.