Bouch returned repeatedly to the problem of bridging the two great East Coast firths. It is not to be confused with the numerous Firths that surround Orkney. This is a list of waterways, defined as navigable rivers, canals, estuaries, lakes, or firths. Other tidal inlets include firths, voes and bays. For Scottish estuaries, please see under firths and sea lochs. Cumbric place names are found in Scotland south of the firths of Forth and Clyde. The "Britannias" took their names from great Britons, former Star class locomotives, and Scottish firths. Firths designs used features such as sans serif faces and asymmetrical compositions. Some such bodies of water could also be called firths, fjords, estuaries, straits or bays. Firths are to be found mostly on the Scottish and northern English coasts.