The street layout, typical of the old quarters of many northern European cities, is made especially picturesque in Edinburgh, where the castle perches on top of a
rocky crag, the remnants of an
extinct volcano, and the main street runs down the crest of a ridge from it. This "
crag and tail" landform was created during the
last ice age when receding
glaciers scoured across the land pushing soft soil aside but being split by harder crags of volcanic rock. The hilltop crag was the earliest part of the city to develop, becoming fortified and eventually developing into the current Edinburgh Castle. The rest of the city grew slowly down the tail of land from the Castle Rock. This was an easily defended spot with marshland on the south and a man-made
loch, the
Nor Loch, on the north. Access to the town was restricted by means of various gates (called ports) in the
city walls, of which only fragmentary sections remain. The original strong linear spine of the Royal Mile only had narrow closes and wynds leading off its sides. These began to be supplemented from the late 18th century with wide new north–south routes, beginning with the
North Bridge/
South Bridge route, and then
George IV Bridge. These rectilinear forms were complemented from the mid-19th century with more serpentine forms, starting with Cockburn Street, laid out by Peddie and Kinnear in 1856, which specifically improved access between the Royal Mile and the newly built
Waverley Station. The
Edinburgh Improvement Act 1867 (
30 & 31 Vict. c. xliv) further added to the north south routes. This was devised by the architects
David Cousin and
John Lessels. It had quite radical effects: • St Mary's Wynd was demolished and replaced by the much wider St Mary's Street with all new buildings. • Leith Wynd which descended from the High Street to the Low Calton was demolished. Jeffrey Street started from Leith Wynd's junction with the High Street, opposite St Mary's Street, but bent west on arches to join Market Street. • East Market Street was built to connect Market Street and New Street. • Blackfriars Street was created by the widening of Blackfriars Wynd, removing all the buildings on the east side. •
Chambers Street was created, replacing N College Street and removing Brown Square (west) and Adam Square (east). It was named after the then
Lord Provost of Edinburgh,
Sir William Chambers, and his statue placed at its centre. • Guthrie Street was created, linking the new Chambers Street to the
Cowgate. ==Sections==