beach coastline Cornish cornwall England english fun Great Britain holiday landscape leisure low natural nature pleasure sand sandy sea tide vacation bank bend boat clouds field meadow moored motor launch Mud river sky trees verge water cave cliff hidden hillside ocean rock shore waves boulders granite granitic hard rocks atlantic bungalow home house surf view blue danger flora flowers spring Towan Head treacherous wild black dark island rocky pink coastal Molluscs mussels Mytilus seascape shellfish