Approximately halfway between Logatec and the Ad Pirum fort, the main Roman road was controlled by the Lanišče barrier on a natural shelf. The barrier line with the fortlet extended from the northwest to the southeast and its central part was a smaller square fortlet. The latter was an excellent viewpoint, since to the east, the strategic points of the Ajdovski zid above Vrhnika and the Gradišče Hill, below which the Brst near Martinj Hrib barrier is located, can be seen.
To the north of the fortlet, we can follow the barrier for approximately 5 m. Lower on the slope, parallel to today’s forest path, runs an older cart track, allegedly the route of a former Roman road. In its cut, we can, on certain spots, see larger quantities of lime mortar and quarry stones, which are probably the remains of the northern barrier wall. Southeast of the fortlet, the barrier wall is better preserved. It first runs along the edge of a natural shelf above the road, then turns south, where it ends in a large rock mass on the slopes of the Srnjak Hill. The entire preserved wall on this barrier thus measures around 315 m and until today, no towers have been discovered on it.
The reconstructed fortlet in Lanišče is almost of a perfect square shape. The entrance is on the south-western side, where an embrasure is located, made of a single piece of limestone. The second embrasure, incorporated in the north-eastern side of the fortlet, was made of a single piece of sandstone. At the top of the fortlet, which is somewhat narrower, a battlement is clearly visible as well. In the interior of the fortlet, wooden residential military buildings were once attached to the wall.
The Lanišče fortlet was used only briefly in the second half of the 4th century, which has been concluded on the basis of the discovered archaeological finds.