 The Wirral Peninsula lies to the north-west whilst the plain merges with the South Lancashire Plain in the embayment occupied by Manchester to the north.In detail, the plain comprises two areas with distinct characters, the one to the west of the Mid Cheshire Ridge and the other, larger part, to its east.The plain is the surface expression of the Cheshire Basin, a deep sedimentary basin that extends north into Lancashire and south into Shropshire.