The weir here, which was once much higher, had the same purpose as that at Torr Vale Mill,
providing a supply of water for a water-wheel via a head-race tunnel. The entrance of
the tunnel is below the stone wall next to the railings (though not visible from this
side of the river). On the opposite bank of the river is a fine natural outcrop of a
sandstone known geologically as the Woodhead Hill Rock which forms the walls of the gorge.
On the way to the next location, on the left by a wall half-way up the slope, you pass
what is thought to be the remains of an engine bed in Rock Mill.