 To the south of the Downs in the western part of the county are the sandstone Surrey Hills, while further east is the plain of the Low Weald, rising in the extreme southeast to the edge of the hills of the High Weald.The Downs and the area to the south form part of a concentric pattern of geological deposits which also extends across southern Kent and most of Sussex, predominantly composed of Wealden Clay, Lower Greensand and the chalk of the Downs.Much of Surrey is in the Metropolitan Green Belt.