[Karolgadge]

Just read this after re-activating membership. Yes, you're quite right about the farms being called 'vaccaries' but the exact meaning of the term is more accurately rendered as a 'cattle farm' from the latin for cow 'vacca' (a root from which we derive our modern term 'vaccine'). Occasionally it is still possible to see the outlines of medieval vaccaries (at Brennand near Dunsop Bridge for example) but obviously due to the urban development of Accrington, traces are impossible to find here.
The Black monks or, rather 'Black Friars' is the common designation of the Dominican order or Order of Preachers (OP). Friars did not reside in monasteries or priories. Cistercian habits in the medieval period were of undyed wool so would have appeared greyish in colour.
As a boy living in Accrington I was familiar with the hoary old tales of 'Black Abbey' and the tunnel which supposedly led to Whalley. As I grew older, I learned to discount these myths; the real history of local monasticism is much more interesting.