On our run into the marina yesterday (last but one, gorgeous day today, then off through wonderful Lancashire tomorrow on our last cruise of the season) we went through the Foulridge tunnel, great fun. But before that at Foulridge we stopped and looked at the Lime kiln.
Probably built at the same time as the canal, 1790 -96, it is one of two that were built each end of the tunnel for the lime mortar for the tunnel itself.
Prior to the canal the limestone would have been brought in by ponies over old packhorse ways.