The coast of Ceredigion is made up of a long coastal plain that contains high cliffs, coves, large bays and estuaries. The coastal plain gets narrower towards the more mountainous north of the county and is cut by the wide estuaries of the Teifi and the Dyfi. The broad and fertile Teifi valley is ideal for dairy farming and mixed farming. Heavy rainfall washes the minerals out of the soil and results in the mountainous areas of the county having relatively poorer, acidic soils. The plough line can be as low as 700 feet, which restricts cultivation.