Natural History Museum — Merrion Street Upper

Detached rectangular-plan two-storey museum building, erected 1856-7, having three-bay front elevation, twelve-bay north elevation and ten-bay south elevation, three end bays of long elevations projecting slightly. Hipped slate roof with central rooflight, leaded ridges and hips, and simple brick chimneystacks. Overhanging Portland stone eaves on corbel brackets separated by carved leaf panels over rinceau frieze having rope-moulded fillet. Ashlar granite walling, rusticated to ground floor, having stepped quoins, Portland stone dressings including grotesque panels; south elevation is of roughly coursed rubble masonry with granite quoins to projecting ends. Square-headed window openings to north elevation ground floor with plain reveals and continuous sill course; similarly detailed ground floor windows to south elevation, sill course to first three projecting bays only, otherwise having projecting granite sills. Square-headed blind openings to upper storey of south elevation, later segmental-headed openings inserted at lower level c. 1900 and having brick voussoirs, projecting sills and top-hung casement windows. Other openings are blind, square-headed to ground floor of front elevation with sill course; round-headed niches to first floor set in square-headed pedimented surrounds having scrolled brackets, grotesque friezes and panelled aprons beneath continuous sill course, front elevation and projecting bays of north elevation having central niches only, flanked by flat-headed applied Portland stone surrounds with drip-mouldings. Central pedimented entrance with double Gibbs surround and double-leaf four-panel timber doors flanked by quadrant dwarf walls with ball finials. Located between Government Buildings and Leinster Lawn, with grassed area to front enclosed by cast-iron railings supported on granite piers, matching those to Leinster House. Engineered interior retaining original layout, fixtures and fittings. Access into full-width vestibule, having quarter-turn cantilevered timber staircases to either side, barley-twist balustrades, ramped handrails. Red and black quarry tiled floor, with cast-iron ventilation grilles throughout ground floor. Full-length galleries to ground and upper floors, triple-height upper gallery having balconied upper levels, lit from above, original roof structure above later ley-light of c. 1900. Supporting cast-iron columns to ground floor; balconied upper level supported on cast-iron supporting structure encased in panelled posts and beams, with scrolled brackets; cast-iron balcony parapets, diagonal braces with central medallions, framed by guilloche borders; and with recent glazed parapet to upper level. Original glazed timber display cases throughout. Rear stairs hall having bifurcated stone staircase with cast-iron balustrade, coffered ceiling, and lit by Venetian window with columnar surround.