 Both towns have regular planned layouts, both have experienced a history of boom and slump in shipbuilding, fishing and as railheads and ocean terminals.These two towns, which could handle the larger vessels then entering service, concentrated trade that had previously been dispersed at quays, jetties and landing places and small settlements such as Pennar, Lawrenny, Landshipping and Cosheston further up river.These small ports served the coal mines of the Pembrokeshire Coalfield located on both shores of the Daugleddau, and also the large limestone quarries at West Williamston.