Question: The destroyed royal fortress of Marchmont is situated across the river from which Scottish town?

Context paragraphs:
Bashkiriya National Park: Bashkiriya National Park ( Bashkort:"Башҡортостан милли паркы", Russian: "Башкирия (национальный парк)"), covers a large contiguous forest on the southern end of the Urals mountains.  The park is an important buffer between the industrialized flatlands to the west, and the mountainous and sparsely-populated Shulgan-Tash nature reserve and Altyn-Solok ("Golden Bee Tree") entomological reserve to the east and north.  Bashkirya National Park lies between the Nugush River (and the popular recreational zone of the Nugush Reservoir), and the southern bend of the Belaya River.  The park features deep river valley cuts in a karst topography.  It is known for a natural bridge across the river Kuperlya.  The park is situated across three districts (Meleuzovsky, Kurgachinsky and Burzyansky) of the Republic of Bashkortostan (also known as "Bashkiriya").

Marchmont: Marchmont is a mainly residential affluent area of Edinburgh, Scotland.  It lies roughly a mile to the south of the Old Town, separated from it by The Meadows and Bruntsfield Links.  To the west it is bounded by Bruntsfield; to the south-southwest by Greenhill and then Morningside; to the south-southeast by The Grange; and to the east by Sciennes.  The name derives from the wife of Sir George Warrender who was daughter to Hume Campbell of Marchmont.  Marchmont is an archaic name for Roxburgh Castle, a now destroyed royal fortress in the Scottish marches.

Royal Fortress of the Concepcion: The fortress of Real Fuerte de la Concepción (English: Royal Fortress of the Conception) is a star fortress built in the Vaubanesque style.  It is located 0.6 mi west of the village of Aldea del Obispo in the province of Salamanca, western Spain, part of the autonomous community of Castile and León.  The fortress was constructed there because of its position of great strategic significance due to its proximity to the border between Spain and Portugal which lies 0.4 mi to the west of the fortress.  The Fortress of the Concepcion is also opposite the Portuguese castle fortress of Almeida which lies 5.5 mi west-north-west of the fortress.  In 2006, the derelict fortress was sold privately and the site was renovated into a luxury hotel which opened in 2012.

Roxburgh Castle: Roxburgh Castle is a ruined royal castle that overlooks the junction of the rivers Tweed and Teviot, in the Borders region of Scotland.  Its castleton developed into the royal burgh of Roxburgh, which the Scots destroyed along with the castle after capturing it in 1460.  Today the ruins stand in the grounds of Floors Castle, the seat of the Duke of Roxburghe, across the river from Kelso.

Scarborough Castle: Scarborough Castle is a former medieval Royal fortress situated on a rocky promontory overlooking the North Sea and Scarborough, North Yorkshire, England.  The site of the castle, encompassing the Iron Age settlement, Roman signal station, an Anglo-Scandinavian settlement and chapel, the 12th-century enclosure castle and 18th-century battery, is a scheduled monument of national importance.

Bruree: Bruree (Irish: "Brú Rí" , meaning "Fort of the King" ) is a village in south-eastern County Limerick, Ireland, on the River Maigue.  It takes its name from the nearby ancient royal fortress, the alternative name of which from the earliest times into the High Middle Ages was Dún Eochair Maigue or the "Fortress on the Brink of the Maigue" Other very old spellings and names include Brugh Righ, and Brugh Ri; literally, Brugh=Fort and Ri=King.

Princess Royal Fortress: Princess Royal Fortress also known as Albany Forts was a fortress on the northern shore of Atatürk entrance on Princess Royal Harbour on Mount Adelaide overlooking King George Sound in Albany, Western Australia.  It now operates as a museum.

Fernhill, South Lanarkshire: Fernhill is a residential district in the Scottish town of Rutherglen in the South Lanarkshire Council area.  It is situated south of the River Clyde and borders the Rutherglen districts of High Burnside to the north and Cathkin to the east, the Glasgow district of Castlemilk to the west, and the fairways of Blairbeth Golf Club (which closed in 2015) to the south.  Fernhill's location on a steep incline which is part of the Cathkin Braes range of hills offers an excellent view over the south and east of Glasgow.  Fernhill is within the "Rutherglen South" ward of the South Lanarkshire area; local councillors include the experienced politician Robert Brown.

Newton, South Lanarkshire: Newton is a mainly residential district in the Scottish town of Cambuslang in South Lanarkshire Council area (part of the " Cambuslang East" ward).  It is situated south of the River Clyde - the river borders the district to the north.

Bede House, Old Aberdeen: The Bede House in Old Aberdeen, Scotland, is a 17th-century Scottish town house.  It was built in 1676 as a residence for Bailie William Logan and his wife Jean Moir of Stoneywood.  During the late 18th century, Old Aberdeen Bedesmen moved from their original hospital beside St Machar’s Church to the former Logan house in Don Street.  In the 19th century the house changed hands.  It was first owned by the Burgh of Old Aberdeen, then, by the City of Aberdeen after the merger of the two burghs in 1891.  The house was refurbished by the City of Aberdeen Council in 1965.  It was divided into two flats or apartments.  The flats are now in private ownership.  Much of the 17th-century building is in its original form.  It is an excellent example of an L-shaped Scottish Town House, built on three floors with an attic.

Supporting paragraphs: Marchmont Roxburgh Castle
Answer: Kelso