Where the western basal drift intersected the main slanted fault plane at five hundred and twelve paces depth, the ancient royal survey corps had carried out a load-bearing masterpiece. The fault zone was exposed at the basal plane as a three-pace-wide band of dark chlorite gouge and snapped earth-shaking clay. It had showed up higher in the mountain as a crumbling shale collapse in the courtyard and an eighty-foot void along the stairwell.
Instead of timbering the crossing with temporary fir posts that would rot over decades, the ancient engineers had spanned the fault with a massive, self-supporting keystone arch cut from massive stone blocks of imported pink granite. The arch was three feet thick, resting on dressed granite footings that were mortised six feet into the unbending basement banded rock on either side of the shear zone.
Kezra Venn knelt beside the northern pier of the arch. She ran her brass measuring tongs over the dressed joints. Her eyes traced the spatial posture of the stonework with intense concentration. Under Rule #2 of cartographic exchanges, no load-bearing element could cross the outer boundary plane of a parcel without invalidating the sign-off.
“Look at the clearance, Yseld,” Kezra pointed out. She held her lantern close to the granite keystone. “The entire keystone arch sits twelve paces inside the 1,024-pace Horizon boundary plane. The ancient builders didn’t try to bridge the fault into the outer mountain. They contained the dynamic stress wholly within this parcel’s load-bearing footprint. The fault moves. But…
