The word “slob” is a provincial term, and applied to banks of mud in the same way that the word “warp” is used to signify similar formations in the River Humber.
Second Report of the Commissioners appointed pursuant to the Act 5 & 6 William IV cap 67 for the improvement of the navigation of the River Shannon; with maps, plans, and estimates HMSO, Dublin 1837
Irish waterways history 