Flat-bottomed rails are fastened to the sleepers by hookheaded spikes, the heads of which project over the flanges.
Naval preparations went on apace at all the dockyards, and numbers of flat-bottomed boats were built or repaired at the northern harbours.
Formerly of some importance, the harbour can no longer be entered by large vessels, and goods are transhipped into flat-bottomed lighters for conveyance ashore.
Flat-bottomed boats were gradually collected at Boulogne.
Small springs of fresh water are frequent and there are 'several shallow lakes or pans - flat bottomed depressions with no outlet.
