Dead & gone

It's funny, isn't it, how easily you can overlook things? This stone has obviously been here for years, and I must have walked near to it several times without noticing it. It's on the canal bank in the grounds of Saltaire's URC church. Even having noticed it, I am unsure exactly what it is. Clearly the letters L&LCCo stand for the Leeds & Liverpool Canal Company. This was the company formed in 1768 to construct the canal, to enable the transport of raw materials (including limestone from Skipton) to the developing wool and industrial centres of Bradford and Leeds, as well as the exporting of finished products to the Americas, via the port of Liverpool. The company must have ceased when the canals were nationalised in 1948. The stone looks like a gravestone for the defunct company! But I'm sure it had some proper purpose. I have no idea what the "B" means.