Question: Which castle was the stronghold of a family whose surname derived from the Gaelic term "dubh glas" meaning 'black stream'?

full_context: Document 1: McAllister (surname): McAllister is a surname from Scotland and Ireland that is the anglicised form of Gaelic Mac Alasdair, meaning son of Alasdair. Alasdair is the Gaelic form of the first name Alexander. A branch of the MacDonalds or MacDonnells of Ireland and Scotland. Commonly found throughout Ulster.
Document 2: Douglas (surname): Douglas (occasionally spelled "Douglass") is a common surname of Scottish origin, thought to derive from the Gaelic "dubh glas", meaning "black stream". There are numerous places in Scotland from which the surname is derived. The surname has developed into the given name "Douglas". "Douglas" is a habitational name, which could be derived from any of the many places so-named. While there are numerous places with this name in Scotland, it is thought, in most cases, to refer to Douglas, South Lanarkshire, the location of Douglas Castle, the chief stronghold of the Lords of Douglas. The Scottish Gaelic form of the given name is "Dùbhghlas"; the Irish language form it is "Dúghlas", and "Dubhghlas", which are pronounced ] . According to George Fraser Black, in southern Argyllshire the surname is an Anglicised form of the surnames "MacLucas", "MacLugash" (which are derived from the Gaelic "Mac Lùcais").
Document 3: Macaulay family of Lewis: The Macaulay family of Uig in Lewis, known in Scottish Gaelic as Clann mhic Amhlaigh, were a small family located around Uig on the Isle of Lewis in the Outer Hebrides of Scotland. There is no connection between the Macaulays of Lewis and Clan MacAulay which was centred in the Loch Lomond area, bordering the Scottish Highlands and Scottish Lowlands. The Macaulays of Lewis are generally said to be of Norse origin because of the etymology of their surname and also because of the islands' Viking Age past. However, a recent analysis of the Y-DNA of men with Scottish surnames has shown that a large number of Hebridean Macaulays are of Irish origin. In the 17th century, however, tradition gave the Macaulays an Irish (or Gaelic) origin. By the end of the 16th century the dominant clan on Lewis was Clan Macleod of The Lewes. Other notable Lewis clans were the somewhat smaller Morrisons of Ness and the even less numerous Macaulays of Uig. The Macaulays were centred in the area surrounding Uig on the western coast of Lewis, and had a deadly, long-standing feud with the Morrisons, whose lands were located on the northern coast around Ness. Today the Lewis surname "Macaulay" is considered to be a sept name of the Macleods of Lewis. There are two other nearby clans of Macaulays who may, or may not, be connected to the Lewis clan—the Wester Ross Macaulays, and the Uist MacAulays.
Document 4: Kenmure Castle: Kenmure Castle is a country house in Dumfries and Galloway, south-west Scotland. The site was occupied from the Middle Ages, and the house incorporates part of a 17th-century castle. This was remodelled in the 19th century, but the house has been derelict since the mid-20th century. It was the seat of the Gordon family of Lochinvar, later raised to the peerage as Viscounts of Kenmure. The castle is located in The Glenkens, 1 mi south of the town of New Galloway. The ruin is a category B listed building and a scheduled monument.
Document 5: Douglas Castle: Douglas Castle was a stronghold of the Douglas family from medieval times to the 20th century. The first castle, erected in the 13th century, was destroyed and replaced several times until the 18th century when a large mansion house was built in its place. This too was demolished in 1938, and today only a single corner tower of the 17th-century castle remains. The castle was the former family seat of the Prime Minister, Sir Alec Douglas-Home. The castle was located around 1 km north-east of the village of Douglas, South Lanarkshire, in south-west Scotland. The remains are protected as a category C listed building.
Document 6: Dundas Castle: Dundas Castle is a 15th-century castle, with substantial 19th-century additions by William Burn, in the Dalmeny parish of West Lothian, Scotland. The home of the Dundas family since the Middle Ages, it was sold in the late 19th century and is currently the residence of politician and businessman Sir Jack Stewart-Clark.
Document 7: MacAlasdair: MacAlasdair is a masculine surname in Scottish Gaelic. The name translates into English as "son of "Alasdair"". The feminine form of the name is NicAlasdair, which translates into English as "daughter of "Alasdair"". These surnames originated as a patronyms, however they no longer refer to the actual name of the bearer's father. There are numerous Anglicised forms of "MacAlasdair".
Document 8: Ardrossan Castle: Ardrossan Castle is situated on the west coast of Scotland in the town of Ardrossan, Ayrshire. The castle, defended by a moat, stands on a ridge above the town. There is a keep dating from the fifteenth century, and a vaulted range containing a kitchen and cellars. In a deep passageway there is a well. Part of the keep remains up to the corbels of the parapet, but it is in ruins. The original castle, owned by Clan Barclay, was partly destroyed during the Wars of Scottish Independence. This event, in which the English garrison were slaughtered, became known as "Wallace's Larder," a name which is still applied to the remaining vaults. Rebuilt by Clan Montgomery in the 15th century, Ardrossan later fell into disuse and was partially demolished by the soldiers of Oliver Cromwell in the 17th century who used the stones to help construct the Ayr Citadel.
Document 9: Dickson (surname): Dickson or, as is common in England, "Dixon," is a patronymic surname, traditionally Scottish and thought to have originated upon the birth of the son of Richard Keith, son of Hervey de Keith, Earl Marischal of Scotland, and Margaret, daughter of the 3rd Lord of Douglas. "Nisbet in his Heraldry (Edinburgh 1722) says 'The Dicksons are descendants from Richard Keith, said to be a son of the family of Keith, Earls Marischals of Scotland' and in proof thereof carry the chief of Keith Marischal. This Richard was commonly called Dick and the 'son' was styled after him. The affix of son in the Lowlands answering the prefix Mac in the Highlands." As a result, Clan Dickson is considered a sept of Clan Keith. Richard Keith's son, Thomas, took the surname "Dickson," meaning "Dick's son" or "Richard's son." Thomas Dickson (1247–1307) himself has quite a history. He was associated in some way with William Wallace, and was killed by the English in 1307 in battle. Tradition states he was slashed across the abdomen but continued fight holding the abdominal wound closed with one hand until he finally dropped dead. He is buried in the churchyard of St Brides, Douglas, and his marker shows him with a sword in one hand holding his belly with the other. Robert the Bruce made him Castellan of Castle Douglas the year before he was killed.
Document 10: Eilean Dubh: Eilean Dubh meaning 'Black Island' in Scottish Gaelic could refer to:
Document 11: Fetteresso Castle: Fetteresso Castle is a 14th-century towerhouse, rebuilt in 1761 as a Scottish gothic style Palladian manor, with clear evidence of prehistoric use of the site. It is situated immediately west of the town of Stonehaven in Kincardineshire slightly to the west of the A90 dual carriageway. Other notable historic fortified houses or castles in this region are Dunnottar Castle, Muchalls Castle, Fiddes Castle, Cowie Castle and Monboddo House.
Document 12: Morrison (surname): Morrison is an English-language surname. The name is derived from a patronymic form of the English "Morris". The personal name "Morris" sometimes is a variant of "Maurice", and was quite popular in the Middle Ages. In Scotland the surname is sometimes also an Anglicised form of the Scottish Gaelic "MacGilleMhuire", a surname meaning "son of the servant of (the Virgin) Mary". The Scottish surname "Morrison" is also sometimes an Anglicised form of the Irish "O'Muirghesasain", meaning "descendant of "Muirgheas"". In Ireland the surname is sometimes an Anglicised form of the Irish "Mac Muiris", a surname derived from the patronymic form of "Muiris". The Irish personal name "Muiris" derives from the Gaelic adjective Mor or the Gaelic word Muir.
Document 13: Delaney (surname): Delaney is an Irish surname derived from the Gaelic "Ó Dubhsláine", "Dubh" meaning black and "Slaine" for the River Slaine (Slaney). DeLaney is also of Norman origin. There is a branch of Dulaneys in the United States who trace back to a Thomas Delany. Thomas's son, Daniel, claimed to have been descended from Dr. Gideon Delaune, a Huguenot physician and theologian and founder of the Apothecaries' Hall. Hence, there are multiple discussions among genealogical circles as to the origin of Delaney since it can be anglicized Gaelic or anglicized French.
Document 14: Caerlaverock Castle: Caerlaverock Castle (from "caer laverock", "lark castle") is a moated triangular castle first built in the 13th century. It is located on the southern coast of Scotland, 11 km south of Dumfries, on the edge of the Caerlaverock National Nature Reserve. Caerlaverock was a stronghold of the Maxwell family from the 13th century until the 17th century when the castle was abandoned. It was besieged by the English during the Wars of Scottish Independence, and underwent several partial demolitions and reconstructions over the 14th and 15th centuries. In the 17th century, the Maxwells were created Earls of Nithsdale, and built a new lodging within the walls, described as among "the most ambitious early classical domestic architecture in Scotland". In 1640 the castle was besieged for the last time and was subsequently abandoned. Although demolished and rebuilt several times, the castle retains the distinctive triangular plan first laid out in the 13th century. Caerlaverock Castle was built to control trade in early times.
Document 15: Barnbougle Castle: Barnbougle Castle is a much-altered tower house on the southern shore of the Firth of Forth, between Cramond and Queensferry, and within the parish of Dalmeny. It lies within the Earl of Rosebery's estate, just northwest of Dalmeny House. Although its history goes back to the 13th century, the present castle is the result of rebuilding in 1881 by the 5th Earl of Rosebery, who served as Prime Minister from 1894–1895.
ground_truth: Douglas Castle