List of hill passes of the Lake District

About 500 million years ago[1] in the late Cambrian and early Ordivician periods,[2] the region was situated where the Iapetus ocean floor was being subducted under the Avalonia plate.[3] Sedimentary material became metamorphosed to the Skiddaw slates found in the north and west.[4] For a relatively short time of 5 million years Ordovician[5] volcanoes ejected the Borrowdale volcanic rocks – firstly lavas (mostly andesite}[6] and later pyroclastic rocks[7] found in the more central part of the region. The ejection of rock was extreme by world standards and it produced deposits at least 6,000 metres (20,000 ft) deep.[8] When the Baltica-Avalonia and Laurentia continents collided some 420 million years ago in the Caledonian orogeny there was folding of the slate and fracturing (faulting) of the more brittle volcanic rock.[3][9] The whole region was then uplifted again by a batholith of granite mainly in the Carboniferous period although the granite remains largely below the surface.[10][11] The high ground became gradually eroded and to the south the land subsided.[1][12] In the south 8,000 metres (26,000 ft) of Windermere Supergroup sediment formed in the Silurian period with Coniston Limestone towards its base.[13] Overall cover of limestone eroded away.

In the north, slaty rocks now form a smooth topography with sharp ridges although the hills can still be quite high – 931 metres (3,054 ft) in the case of Skiddaw. Centrally the pyroclastic tuff rocks [1] give a knobbly terrain such as that around Scafell Pike, 978 metres (3,209 ft), England's highest mountain.[14][15] To the south is a mostly less hilly area.[1]

Ribbon lake formed by glacial erosion – Wast Water in Wasdale

From about 2 million years ago glacial erosion then greatly modified the landscape.[1][16] Glaciers formed preferentially at existing streams which had developed at the many rock faults produced by crushing during the continental collision. The terrain was ground away leaving characteristically steep-sided glacial valleys which became ribbon lakes.[1] On the Rossett Pass (see below) Rossett Gill is an example of a geological fault and the glacier that descended from it created the Mickleden and Great Langdale valleys below.[17] Taken as a whole the region is characterised by mountain ridges splaying out from a central core. The intervening valleys have been made by glaciers flowing outward along the lines of the previous streams draining the dome of the Lake District.[1]

Historically the region was suitable for sheep hill farming and from medieval (or possibly Roman) times there was a substantial mining industry for rocks and minerals.[1] The Romans had built a high-level military road north–south right through the region on its eastern edge at High Street and another road through the Hardknott and Wrynose passes for travel between forts at Ravenglass and Ambleside.[18] Travelling between valleys was difficult on foot or by pony because of the steep passes across the mountainous ridges. With no roads suitable for wheeled traffic until the late 18th century, for long-distance transport of goods long trains of horses were used with ridge routes being preferred although Esk Hause and Stake Pass (see below) are thought to have been used in this way. However, for travel within the region, routes were best kept as low as possible consistent with avoiding excessive detours so summits and ridges were to be avoided as far as possible.[19]

In the late 18th century the region started to become popular with travellers and the "Lake Poets" began seeing the lakes and mountains as beautiful rather than horrifying.[20] In Victorian times, encouraged by the arrival of the Kendal and Windermere Railway,[1] a tourist trade developed. In the mid twentieth century Alfred Wainwright inadvertently encouraged further recreational use with his series of books A Pictorial Guide to the Lakeland Fells which described detailed routes to the major summits. His considerable knowledge of the district allowed him to make use of the ancient tracks although his focus was not on the ridge passes themselves.[21]

The following individual volumes are part of a boxed set:

• Wainwright, Alfred (2008). The Complete Pictorial Guides: A Reader's Edition (Pictorial Guide Lakeland Fells). Frances Lincoln. ISBN 978-07112-2953-2.

• Wainwright, Alfred (2009). The Outlying Fells of Lakeland. Frances Lincoln. ISBN 978-0-7112-2952-5.(same content as first 1968 edition)

• Smith, Alan (2010). Landscapes of Cumbria, No. 4: Lakeland rocks : an introductory guide. Rigg Side Publications. ISBN 978-0-9544679-3-7.
• Turnbull, Ronald (2011). Granite and grit : a walker's guide to the geology of British mountains. London: Frances Lincoln. ISBN 978-0-7112-3180-1.