The geology of the Yorkshire Dales National Park in northern England largely consists of a sequence of sedimentary rocks of Ordovician to Permian age.
The core area of the Yorkshire Dales is formed from a layer-cake of limestones, sandstones and mudstones laid down during the Carboniferous period.
[1] Folded and faulted rocks of Silurian age (444 - 419 Ma) form the Howgill Fells in the northwest of the national park and give that area a character quite distinct from the rest of the Yorkshire Dales.
A suite of sandstones with siltstones and mudstones assigned to the Coniston Group form the bulk of the Howgills, including the 676m high summit known as The Calf, highest in the range.
The lower part of this sequence is formed by the sandstones of the Wray Castle and Screes Gill formations which are found along the southeastern edge of this range.
Associated with it around the Rawthey valley are a number of felsitic dykes and sills; all are grouped by geologists within the ‘Lake District Minor Intrusion Suite’.
[5] Early Permian age conglomerates and sandstones assigned to the Appleby Group overlie the Coal Measures strata near Ingleton.
[7] Drumlins are a particular feature on the margins of the park between Skipton and Long Preston in Ribblesdale and onward to Kirkby Lonsdale then north to Sedbergh.
The solubility of the limestone in weakly acidic water has resulted in the development of a wide range of surface karst features such as limestone pavements, dry valleys, sinkholes and resurgences along with very extensive cave networks including the Three Counties System which, with over 86km of known passage, is the longest in the UK.
There are clusters of landslides within Coverdale and the valley of the Walden Beck to its northwest, as well as upper Nidderdale just outside of the national park.