Which castle south-southwest of Montrose is named after the red sandstone it's built from?
Lunan, Angus:  The 15th-century Red Castle, so called from the red sandstone it is built from, is located 500 m to the south of the hamlet, on the south bank of the Lunan Water. Red Castle, Angus:  It is about 4 mi south-southwest of Montrose.
i don't know