Carnwath, Main Street, Boundary Walls And Railings, Including Graveyard, St Mary's Aisle

St Mary's Aisle, including graveyard, boundary walls and railings, Main Street, Carnwath

St Mary's Aisle is a small, buttressed, rectangular-plan stone building that survives as a remnant of Carnwath Collegiate Church. The collegiate church was founded in 1424 by Thomas, the first Lord Somerville, who established a collegiate foundation for a provost and six prebendaries and expanded an existing church built on the site in 1386. St Mary's Aisle was constructed as part of this 1424 phase of work and originally served as the north transept of the collegiate church.

The aisle is built of dressed ashlar with stepped stone skews and a stone slab roof. The north entrance gable features a pointed arched central entrance door with studded boarded doors, set beneath a highly decorative five-light traceried window with decorative coloured stained glass panels. The south gable contains an arch, now infilled with stone and the Denham family memorial, which formerly linked the aisle to the main collegiate church. A circular traceried window with hoodmould extends to the apex of this gable. Shouldered, side and corner buttresses with niches, pitched stone caps and decorative carved stone foliate finials are similar in style to the adjacent parish church. Stone walled enclosures bound the structure to the south and west, with cast iron railings to the western enclosure.

The collegiate church fell out use for worship after 1799, when it was replaced by the predecessor to the current Carnwath Parish Church. The majority of the collegiate church was subsequently demolished, though the north transept was retained and repurposed as a burial place for local landowners. Several features were added during this period, including a belfry on the south gable and a cross on the north gable. The aisle now stands so closely adjacent to the later parish church that their buttresses interweave, making it impossible to see daylight between them, though they remain separate structures.

Significant alterations, likely dating to the 19th century, include the large pointed arched window, entrance and cross finial to the north gable, and the belfry on the south gable. The buttresses share a similar style with the adjacent Carnwath Parish Church (1865–1869) designed by David Bryce, though sketches by Alexander Archer dated 1837, held by the Royal Commission on the Ancient and Historic Monuments of Scotland, indicate that the buttresses and north gable details of the aisle may predate the parish church.

St Mary's Aisle has served as the mausoleum for the Somerville family since the 16th century. Within the aisle is a tomb with effigies of Hugh, Lord Somerville and his wife, daughter of William Maitland of Leddingtonne, who died in 1549. The tomb has more recently held associations with the Earls of Carnwath and the Lockhart family.

The surrounding graveyard is enclosed by stone walls and railings. Corniced and capped stone gatepiers with low stone, capped walls and tall barley twist wrought iron railings front the main street elevation; these railings date to the 1865–1869 parish church. Earlier and taller rubble walls enclose the graveyard on other sides. The graveyard contains a 16th century recumbent tomb and gravestones from the 17th, 18th and 19th centuries, with other 19th century memorials built within walls near the east entrance area.