WLGS 38 The Knock (Proposed RIGS) [NS 9906 7114] (Figure 125), (Figure 126), (Figure 127), (Figure 128), (Figure 129)

WLC site description

Part of the Quartz-dolerite sills and dykes group of sites

Other designations: AGLV; M-SSSI (adjacent to Petershill); WS (adjacent to Silvermines Quarry); HPWG (adjacent to Bathgate Hills, Knock, Knock A); AGLV

The rocky knoll of The Knock, 200 m south of Hilderston Silvermines quarry, is formed by a steep east-north-east dipping quartz-dolerite sill intruding basalt lavas of the Bathgate Hills Volcanic Formation and sedimentary rocks of the Lower Limestone Formation. Sphaeroidally- weathered dolerite can be seen on the slopes of hill (Figure 128). The summit of the hill (altitude 305 m) is an excellent viewpoint (Figure 125), with an indicator cairn listing the visible hills. The Knock is also a glacially-sculpted Crag and Tail.

This site lies at the end of Petershill SSSI. The site is a mixed SSSI designated for one of the largest areas of herb rich unimproved grassland in West Lothian, supporting over a hundred plant species. Species-rich grassland of this type is an unusual habitat in the Lothians. The site supports regionally uncommon plants, including the Greater Butterfly Orchid; scrub and marsh vegetation add diversity to the area.

(Figure 125) Panoramic view east to south-east from The Knock (305 m) [NS 9906 7114] (WLGS 38) towards Edinburgh and the Pentland Hills.

(Figure 126) The Knock from the north-west [NS 9906 7114] (WLGS 38). Quartz-dolerite sill on the summit intrudes basalt lavas of the Bathgate Hills Volcanic Formation.

(Figure 127) Quartz-dolerite sill, south-east face of The Knock [NS 9906 7114] (WLGS 38). The chilled contact with the basalt lavas of the Bathgate Hills Volcanic Formation can be seen here.

(Figure 128) Sphaeroidal weathering in dolerite on The Knock [NS 9906 7114] (WLGS 38).

(Figure 129) Millenium Stone circle, Knock Farm [NS 9912 7130] (WLGS 38). Cairnpapple Hill on top left (WLGS 20).