that name are to the north, forming the apex of the roughly triangular area, and the major city-centre shopping street Western Road lies to the south. Two roads form important through routes for cross-city traffic: Montpelier Road runs south–north from the city centre to Seven Dials, and the west–east Upper North Street links the city centre to Hove. Both are busy, but traffic is limited in the smaller residential streets. Dyke Road—the ancient route from Brighton to Devil's Dyke and Steyning and eventually on to London—forms the conservation area's eastern boundary except at the southern end, where it extends east of the road to include St Nicholas Church (Brighton's original parish church), Wykeham Terrace and other small parts of West Hill. The land rises gently from the southwest to a summit at Clifton Hill. Writing in 1833, J.D. Parry said that the hill "commands a magnificent view, and has very fine air". John Constable, who stayed in Brighton several times during the 1820s, was less impressed: he described it as "hideous masses of unfledged earth called the country". Nevertheless, he produced several paintings of the area, which provide a record of its appearance just before it became suburbanised. Geologically, Montpelier is built on grassy downland and sheep-pasture, beneath which is chalk. This pattern is repeated across the rest of the city, most of the Sussex coast and for several miles inland. The chalk, "one of the most complete and accessible strata anywhere in Europe", was formed about 100 million years ago. As in other areas where chalk is prevalent, the soil above it is rendzina. Found in thin layers and with a high calcium content, it has a poor agricultural value. In common with the rest of Brighton, the area has a temperate climate: its Köppen climate classification is Cfb. It is characterised by mild, calm weather with high levels of sunshine, sea breezes and a "healthy, bracing air" attributed to the low level of tree cover. Average rainfall levels increase as the land rises: the 1958–1990 mean was on the seafront and about at the top of the South Downs above Brighton. Locally, a distinction is made between the northern part of the area towards the top of the hill—this area is known as Clifton or Clifton Hill—and the lower land to the south and west, as far as the Hove boundary and Western Road, known as Montpelier. The