It appears from tradition, as well as some parish registers still extant, that the lands of Dalcastle (or Dalchastel, as it is often spelled) were possessed by a family of the name of Colwan, about one hundred and fifty years ago, and for at least a century previous to that period. That family was supposed 
to have been a branch of the ancient family of Colquhoun, and it is certain that from it spring the Cowans that spread towards the Border.