This road is pure speculation at the moment although David Ratledge’s account on the Lancs CC website is very persuasive:-
A few pieces of evidence point to the existence of this road. On the direct route there are 4 occurrences of ‘street’ or ‘causeway’ names. The first at Rivington was regarded by Birtill, the Chorley historian, as a Roman road continuing further north along Heapey Fold Lane. The next is at Causeway House Farm at Heapey. Finally at Causeway Farm near Riley Green an old raised road is reported descending to cross the River Darwen below Lodge Farm. It is lost across the golf course but appears further on across Long Lane at Cabin Hill/Woodcock Hill (Ref: Dixon – Journeys through Brigantia – Book 11). Another Causeway Farm is located at Osbaldeston. The direction of all these is towards Ribchester.