Surrey is a county in southern England, in the southwest of London. It is the most wooded county in Great Britain, with 22.4% coverage. Notable beauty spots are Box Hill, Leith Hill, Frensham Ponds, Newlands Corner and Puttenham Common. The county's geology is dominated by the chalk hills of the North Downs, a characteristic escarpment of Upper Cretaceous chalk. This chalk is karstified, waterless with dry valleys and characteristic treeless vegetation. Nevertheless there are no important karst caves. On the other hand there are numerous subterranea which uuse the soft chalk or the neighboring greensand formation.