that formed them. formed that

Photography by the British Geological Survey/NERC Geological British the by Photography Horton Siltstones. Horton Silurian darker limestone, in thinner beds above the falls under the bridge. the under falls the above beds thinner in limestone, darker

rocks were eroded away, taking with them clues to the events events the to clues them with taking away, eroded were rocks

Ribble River Force, Stainforth Kilnsey Limestone and the steeply dipping dipping steeply the and Limestone Kilnsey Carboniferous Middle Craven Faults, and the younger Kilnsey Limestone forms the the forms Limestone Kilnsey younger the and Faults, Craven Middle

After the Variscan, for almost 300 million years, the younger younger the years, million 300 almost for Variscan, the After

The unconformity between the almost horizontal horizontal almost the between unconformity The oldest of the Great Scar Limestones exposed between the North and and North the between exposed Limestones Scar Great the of oldest

www.storiesinstone.org.uk

SW-NE trending folds in the Ribblesdale Fold Belt. Fold Ribblesdale the in folds trending SW-NE

falls is the Chapel House Limestone, at about 340 million years, the the years, million 340 about at Limestone, House Chapel the is falls

Combs Quarry - Photo © British Geological Survey/NERC Geological British © Photo - Quarry Combs

causing movement along the Craven Faults, and creating several several creating and Faults, Craven the along movement causing and supported by the Heritage Lottery Fund. Lottery Heritage the by supported and The light coloured, thick bedded grey rock that forms the face of the the of face the forms that rock grey bedded thick coloured, light The

Carboniferous-, it was subjected to intense folding folding intense to subjected was it Carboniferous-Permian, Landscape Partnership, led by Dales Millennium Trust, Trust, Millennium Dales Yorkshire by led Partnership, Landscape

Lancashire High to the south. During the Variscan, in the the in Variscan, the During south. the to High Lancashire area. The scheme was developed by the Dales Dales Ingleborough the by developed was scheme The area.

Nappa Scar – vertical section © Tony Waltham Tony © section vertical – Scar Nappa

between the Askrigg Block to the north and the Central Central the and north the to Block Askrigg the between and community projects concentrated on the Ingleborough Ingleborough the on concentrated projects community and

crustal stretching or extension created a rift valley system system valley rift a created extension or stretching crustal This project is part of Stories in Stone, a scheme of conservation conservation of scheme a Stone, in Stories of part is project This

The Craven Basin was also affected. Early in the Carboniferous Carboniferous the in Early affected. also was Basin Craven The

also occurred in this area. this in occurred also

limestone by dolomite (dolomitisation) and silica (silicification) (silicification) silica and (dolomitisation) dolomite by limestone

under licence 2017/096 British Geological Survey © NERC © Survey Geological British 2017/096 licence under the High Hills-Back Scar area east of Settle. The replacement of of replacement The Settle. of east area Scar Hills-Back High the

Geological maps derived from 1:50,000 scale BGS Digital Data Data Digital BGS scale 1:50,000 from derived maps Geological Hawes and Gayle Limestones adjacent to the Craven Faults, in in Faults, Craven the to adjacent Limestones Gayle and Hawes

(lead) and baryte were formed in faults in the Yoredale Group Group Yoredale the in faults in formed were baryte and (lead)

producing unconformities. producing Geological figures courtesy of Adrian Kidd Adrian of courtesy figures Geological

Norber Formation. Norber Mineralisation was concentrated in this area, where galena galena where area, this in concentrated was Mineralisation

or falls in sea-level, deposition ceased and erosion occurred occurred erosion and ceased deposition sea-level, in falls or

Text courtesy of Adrian Kidd Adrian of courtesy Text dipping Ordovician dipping structure is dominated by numerous NW-SE trending faults. faults. trending NW-SE numerous by dominated is structure

the geological history of the area. During periods of uplift and/ uplift of periods During area. the of history geological the

eroded, steeply steeply eroded,

the North and Middle Craven Faults, was less stable and its its and stable less was Faults, Craven Middle and North the

illustrations from the two books. two the from illustrations

Movements of the fault system have played an important part in in part important an played have system fault the of Movements

deposited on the the on deposited

and unaffected, but in the south the Transition Zone, between between Zone, Transition the south the in but unaffected, and

Waltham for his generous support in allowing the use of of use the allowing in support generous his for Waltham

Craven Basin, the dividing line being the Craven Fault System. System. Fault Craven the being line dividing the Basin, Craven

basal conglomerate conglomerate basal Group.

northern part of the Askrigg Block remained relatively stable stable relatively remained Block Askrigg the of part northern

The Geodiversity Partnership thanks Dr Tony Tony Dr thanks Partnership Geodiversity Yorkshire North The

southern edge of the Askrigg Block and the northern edge of the the of edge northern the and Block Askrigg the of edge southern

Kilnsey Limestone Limestone Kilnsey where they are overlain by the red beds of the Warwickshire Warwickshire the of beds red the by overlain are they where Wensleydale Granite, intruded about 410 million years ago, the the ago, years million 410 about intruded Granite, Wensleydale

northern , and the project area was located at the the at located was area project the and England, northern

Research Association. Research

The Carboniferous Carboniferous The Measures Group, which occur in the south around Ingleton Ingleton around south the in occur which Group, Measures Coal faulted, folded and intruded by mineral veins. Underlain by the the by Underlain veins. mineral by intruded and folded faulted,

extension created a series of geological blocks and basins in in basins and blocks geological of series a created extension

Waltham and David Lowe and published by the British Cave Cave British the by published and Lowe David and Waltham

the tropical deltaic swamps produced the rocks of the Pennine Pennine the of rocks the produced swamps deltaic tropical the especially in the Transition Zone and Craven Basin, were were Basin, Craven and Zone Transition the in especially

During the Carboniferous, an episode of crustal stretching or or stretching crustal of episode an Carboniferous, the During

‘Caves and Karst of the ’ (2013) edited by Tony Tony by edited (2013) Dales’ Yorkshire the of Karst and ‘Caves the area. Late in the Carboniferous, the humid conditions of of conditions humid the Carboniferous, the in Late area. the deposition of the Warwickshire Group, during which the rocks, rocks, the which during Group, Warwickshire the of deposition

east of Settle. of east

(354 to 330 million years ago) ago) years million 330 to (354

rocks (the Group) occur mainly in the south of of south the in mainly occur Group) Grit Millstone (the rocks More mountain building (the Variscan) occurred after the the after occurred Variscan) (the building mountain More

is available in: available is and now form the line of hills or knolls (for example, High Hill) Hill) High example, (for knolls or hills of line the form now and

were laid down. Preserved now as the gritstone moors, these these moors, gritstone the as now Preserved down. laid were Tropical Seas – Early Carboniferous Period Period Carboniferous Early – Seas Tropical

More detailed information on a wide range of geological topics topics geological of range wide a on information detailed More

a shallow tropical lagoon in the sea, limestone reefs developed, developed, reefs limestone sea, the in lagoon tropical shallow a

greater and thick beds of sandstones, mudstones and thin coals thin and mudstones sandstones, of beds thick and greater

Group Rocks Group

Craven Group in the Craven Basin. Along the southern edge of of edge southern the Along Basin. Craven the in Group Craven

Waltham and published by The Crowood Press. Crowood The by published and Waltham

As time progressed, the extent of the river delta systems became became systems delta river the of extent the progressed, time As

Great Scar Limestone Limestone Scar Great

Great Scar Limestone Group on the Askrigg Block, and the the and Block, Askrigg the on Group Limestone Scar Great

‘The Yorkshire Dales – Landscape and Geology’ (2007) by Tony Tony by (2007) Geology’ and Landscape – Dales Yorkshire ‘The

regions in the area the in regions

harder wearing beds standing out as scars with scree slopes. slopes. scree with scars as out standing beds wearing harder sea-bed, forming the horizontal layers of the Carboniferous Carboniferous the of layers horizontal the forming sea-bed,

Earth history are missing. are history Earth

The key faults and geological geological and faults key The

be found in: found be

resistance to erosion the slopes are distinctively ‘stepped’, with with ‘stepped’, distinctively are slopes the erosion to resistance carbonate from their shells and the sea was deposited on the the on deposited was sea the and shells their from carbonate

Carboniferous period. Over most of the area, 80 million years of of years million 80 area, the of most Over period. Carboniferous

An excellent overview of the geology of the Yorkshire Dales can can Dales Yorkshire the of geology the of overview excellent An

harder sandstones and limestones have different degrees of of degrees different have limestones and sandstones harder seas were full of life, and as these creatures died the calcium calcium the died creatures these as and life, of full were seas

Photo © BGS/NERC © Photo flat before they were swamped by the tropical seas of the the of seas tropical the by swamped were they before flat

Group. Because the alternating bands of soft mudstones with with mudstones soft of bands alternating the Because Group. an unconformity. Those in between are simply missing. The The missing. simply are between in Those unconformity. an

Nappa Scar – Carboniferous basal conglomerate conglomerate basal Carboniferous – Scar Nappa Further reading Further under tropical arid conditions had worn the rocks almost almost rocks the worn had conditions arid tropical under

more than 300m, forming the Yoredale Group or Wensleydale Wensleydale or Group Yoredale the forming 300m, than more on top of the eroded, steeply dipping older rocks, producing producing rocks, older dipping steeply eroded, the of top on

Granite. By the end of the , weathering and erosion erosion and weathering Devonian, the of end the By Granite.

of limestones, mudstones, sandstones with an overall depth of of depth overall an with sandstones mudstones, limestones, of seas covered the area, depositing the Carboniferous limestones limestones Carboniferous the depositing area, the covered seas

and, about 410 million years ago, intruded by the Wensleydale Wensleydale the by intruded ago, years million 410 about and,

level produced repeated cycles (cyclothems) of alternating beds beds alternating of (cyclothems) cycles repeated produced level Between 350 and 330 million years ago, extensive warm tropical tropical warm extensive ago, years million 330 and 350 Between

and Crummack Anticlines, and Studrigg-Studfold Syncline) Syncline) Studrigg-Studfold and Anticlines, Crummack and

from huge river deltas. Over millions of years changes in sea sea in changes years of millions Over deltas. river huge from

Block were uplifted, folded (forming the , Crag Hill Hill Crag Austwick, the (forming folded uplifted, were Block

seen in small outcrops east of . Ribblesdale. in Horton of east outcrops small in seen

and sand was periodically being washed into the tropical sea sea tropical the into washed being periodically was sand and

building interval (the Caledonian), the rocks of the Askrigg Askrigg the of rocks the Caledonian), (the interval building

and sandstones of the Ravenstonedale Group. They are only only are They Group. Ravenstonedale the of sandstones and

The tropical paradise did not last. By 330 million years ago mud mud ago years million 330 By last. not did paradise tropical The

environment. The sea shallowed, and during a major mountain mountain major a during and shallowed, sea The environment. and Ordovician rocks depositing the conglomerates, mudstones mudstones conglomerates, the depositing rocks Ordovician and

(330 to 290 million years ago) ago) years million 290 to (330 The end of the Silurian saw a dramatic change in the local local the in change dramatic a saw Silurian the of end The tropical seas lapped over the worn-down Precambrian, Silurian Silurian Precambrian, worn-down the over lapped seas tropical

Carboniferous Period the area lay in tropical latitudes. Shallow Shallow latitudes. tropical in lay area the Period Carboniferous

(417 to 354 million years ago) ago) years million 354 to (417 Period Carboniferous

centimetres a year, moved continents, so that by the start of the the of start the by that so continents, moved year, a centimetres

Devonian – Desert Tropical Tropical swamps and deltas – Late Late – deltas and swamps Tropical

Ancient crustal plate tectonic movements, at several several at movements, tectonic plate crustal Ancient

formed in a deep ocean basin ocean deep a in formed

brian m reca p

Ingleton Group sandstones and mudstones mudstones and sandstones Group Ingleton

considerable erosion. considerable

545 brian m ca Unconformity and building mountain movements, earth of

s root ncient A sequences separated by unconformities that illustrate intervals intervals illustrate that unconformities by separated sequences

and mudstones formed in a deep ocean basin ocean deep a in formed mudstones and 495

ordovician

60 S 60 the rocks of the area shows a series of geological depositional depositional geological of series a shows area the of rocks the Windermere Supergroup, Ordovician sandstones sandstones Ordovician Supergroup, Windermere

present-day landscape. A vertical geological section through all all through section geological vertical A landscape. present-day

and mudstones formed in a deep ocean basin ocean deep a in formed mudstones and 443

urian l i s

times have culminated with the ice-ages and erosion to form the the form to erosion and ice-ages the with culminated have times 30 S 30 Windermere Supergroup, Silurian sandstones sandstones Silurian Supergroup, Windermere

tropical seas, swamps and tropical forests. The most recent recent most The forests. tropical and swamps seas, tropical

and intrusion of Wensleydale Granite Wensleydale of intrusion and

417

story of the evolution of the area from deep oceans, through through oceans, deep from area the of evolution the of story

Caledonian mountain building - folding, faulting faulting folding, - building mountain Caledonian

ert s de l ica p tro devonian with the landscape we know today. The rocks and fossils tell a a tell fossils and rocks The today. know we landscape the with

unconformity

the ice melted. Millions of years of Earth history have culminated culminated have history Earth of years of Millions melted. ice the Ingleborough rocks! 15 S 15 Erosion of ancient basement rocks producing an an producing rocks basement ancient of Erosion

the ice ages and the way people have influenced the land since since land the influenced have people way the and ages ice the

354

character. Much of it results directly from the rocks, the effects of of effects the rocks, the from directly results it of Much character. s ea s l ica p tro Great Scar Limestone Group Limestone Scar Great A 500 million year story of the Stories

The landscape of the Stories in Stone area has a unique unique a has area Stone in Stories the of landscape The

sandstones sandstones years ago. years in Stone area

Ribblesdale

Yoredale Group limestones, mudstones and and mudstones limestones, Group Yoredale and were deposited over a time interval that spanned 446-417 million million 446-417 spanned that interval time a over deposited were and

A simplified north-south geological section of of section geological north-south simplified A

flows (turbidity currents) in a deep ocean basin, located about 30˚S, 30˚S, about located basin, ocean deep a in currents) (turbidity flows

Craven Group mudstones and sandstones and mudstones Group Craven

N 0 s carboniferou

Supergroup, began life as muddy and sandy submarine sediment sediment submarine sandy and muddy as life began Supergroup, s ta l de and

Millstone Grit Group sandstones Group Grit Millstone

mps wa s l ica p ro T of the Windermere Windermere the of

Pennine Group Measures Coal Pennine sandstones, sandstones, greywacke

the Kilnsey Limestone. Kilnsey the

The grey slates and and slates grey The

and the overlying Carboniferous basal conglomerates of of conglomerates basal Carboniferous overlying the and and formation of mineral veins mineral of formation and

gap or unconformity. unconformity. or gap

Variscan mountain building - folding, faulting faulting folding, - building mountain Variscan Precambrian Ingleton Group, at the base of the waterfall, waterfall, the of base the at Group, Ingleton Precambrian

strata represent a time time a represent strata

year time gap between the steeply dipping slates of the the of slates dipping steeply the between gap time year ert s de l ica p ro T

Supergroup, the missing missing the Supergroup,

290 ian m er p

the concept of the unconformity. There is a 200 million million 200 a is There unconformity. the of concept the

s ea s l ica p ro T rocks of the Windermere Windermere the of rocks

Thornton Force is a classic geological site, illustrating illustrating site, geological classic a is Force Thornton

Ordovician and Silurian Silurian and Ordovician

and l erate mp e T 248 N 20 ic ss tria

Thornton Force - Photo © Adrian Kidd Adrian © Photo - Force Thornton

overlain by the late late the by overlain

s ea s & and l l ica p ro T 205 N 40 ic ss Jura

No deposits in this area this in deposits No erosion before being being before erosion

metamorphism and and metamorphism s ea s erate mp e T 142 s cretaceou

building event, to folding, folding, to event, building

65 N 45 ene g aeo l a p

during a mountain mountain a during and l erate mp e T

24 ene g neo sequence was subjected, subjected, was sequence

As this basement basement this As

1.8

Glacial erosion Glacial (arctic)

s e g a ce I the area. the

Glacial deposition Glacial

in rocks oldest the exposed has rocks younger of erosion inliers),

0.012 Limestone pavements Limestone further east near Horton in Ribblesdale. In these areas (the Craven Craven (the areas these In Ribblesdale. in Horton near east further

Rivers Twiss and Doe in Chapel le Dale, upstream from Ingleton, and and Ingleton, from upstream Dale, le Chapel in Doe and Twiss Rivers Caves

N 54 y Quaternar Antarctic Circle. They are seen in the quarries and waterfalls of the the of waterfalls and quarries the in seen are They Circle. Antarctic

Landslides erate) mp (te

were formed when the area was located at about 60˚S, very near the the near very 60˚S, about at located was area the when formed were

the Stories in Stone area. Stone in Stories the

ecent R

greywacke sandstones and slates of the Precambrian Ingleton Group, Group, Ingleton Precambrian the of slates and sandstones greywacke River terraces River

Over 500 million years old, the ancient roots of the Dales, the the Dales, the of roots ancient the old, years million 500 Over

Waterfalls

A 500 million year story of of story year million 500 A

years ago) ago) years

Gorges

million 417 to 545 (over Periods Silurian

S (MY) S EAR Y

rocks! Ingleborough

l ica g o l Geo Latitude Period g ettin s feature

ion ion ll Mi E G A Ancient Roots – Precambrian, Ordovician and and Ordovician Precambrian, – Roots Ancient

Baxengill Gorge - Photo © Anthony Foster (cc-by-sa/2.0) Buried in ice – Quaternary The Devensian ice deposited extensive areas of ground moraine, Landslides, waterfalls and gorges – as gravelly clays (glacial till), mainly in the valley bottoms which, (1.8 million years ago to the present) at the head of Ribblesdale have been formed into trains of Quaternary Victoria Cave - Photo © Stevie D(cc-by-sa/2.0) rounded hills 20-30m high, 400-700m long and 200-300m wide The last two million years form the Quaternary Period, which is Following the melting of the ice the newly exposed valley sides Victoria Cave is of great interest, not only as an example of cave called drumlins. Together with striations (narrow grooves or divided into the Pleistocene (1.8 million to 10,000 BP) and the were often too steep and unstable, resulting in large landslides development but also because of the animal bones which have scratches cut into the rock surface by pebbles and boulders in the Holocene (10,000 BP to the Present). The Quaternary deposits of as may be seen at The Arks and Falls Foot on the south-western been found in the cave sediments. The cave was first discovered in ice) the alignment of the drumlins provides important evidence the area include the glacial, glaciofluvial and periglacial deposits face of Ingleborough, and Park . On shallow slopes saturated 1837. Dating of stalactites and stalagmites (speleothems) from the of ice flow direction. of the Pleistocene, and the fluvial and slope deposits of the weathered rock often moved downslope as head or solifluction cave has provided a record of climate change dating back 600,000 Holocene. The Pleistocene consisted of a series of glacial periods The evidence indicates that glacial ice moved from the main deposits. More recently, peat deposits have accumulated on the years. Speleothems only develop when water is able to pass separated by warmer periods or inter-glacials. Dales Ice Centre (in the - area) south poorly drained sandstone upland watersheds, and alluvium has through the limestone so their development ceases during periods been deposited along the river flood-plains. Between 478,000 and 423,000 years ago (the Anglian glacial into the Ribble valley to the north of Ingleborough. North of Park of glaciation and resumes in the warmer interglacials. period), the whole area was buried in ice. Massive erosion, Fell it split with one flow moving south-westwards into Chapel Where less resistant rocks, such as mudstone, underlie more caused by the movement and melting of the ice, shaped much le Dale, and another into Ribblesdale, where it was joined by a resistant limestones and sandstones, waterfalls such as Pecca of the landscape; this sculpting continued during another, more flow from the Cam Fell area to the east. A tongue of ice from the Falls and Scaleber Force have formed. In some cases the Scaleber Force recent (the Devensian) ice age (30,000 to 12,000 years ago). Ribblesdale ice developed and moved into Crummack Dale and upstream movement of the waterfalls, by erosion, has created Photography by the British Geological Survey/NERC Clapdale. Eventually the south flowing ice joined the glacier in gorges. Erosion of the alternating mudstones and limestones of Apart from cave deposits, most of the evidence of the Anglian the Craven Lowlands and then moved south-westwards along glaciation was removed during the Devensian ice age. the Carboniferous Kilnsey Limestone have produced this the Ribble valley or eastwards along the Aire valley. impressive stepped waterfall and small gorge.

Karst, caves and limestone pavements – Quaternary The Great Scar Limestone has developed its own distinctive scenery – the karst Warrendale Knotts landscape: a highly detailed, dramatic landscape where the exposed geology The Carboniferous Cove and Gordale becomes the overriding landscape Limestones of the Malham Formation are characteristic of the Ingleborough Dales. exposed in the fault scarp of the Middle Craven Fault. The vegetation reflects the Karst landforms are those produced by the change in geology, south of the fault, from the weathering and erosion (denudation) of limestones to the glacial till covered Bowland limestone. Glaciokarst was formed by ice Shales in the foreground. eroding the overlying soil and weathered rock to expose the limestone below, allowing it to be chemically weathered by slightly acidic rain and soil water. Limestone pavement has been produced where weathering has been concentrated along Gaping Gill – Main Chamber © Tony Waltham the vertical joints forming fissures or grikes separated by blocks or clints. Limestone Distribution of superficial deposits in the area Ribblesdale drumlins © Tony Waltham pavement is a particularly well-developed feature within the Ingleborough Dales and their surrounding uplands. Of the 2600ha Scales Moor - Photo © John Illingworth (cc-by-sa/2.0) of limestone pavement in Britain, about half The ice also transported rocks from far away and, when it melted, melted, numerous meltwater streams developed, underneath, is in the Yorkshire Dales National Park, and An unusual star shaped ‘fluted’ solution hollow on the Carboniferous Great Scar left them behind as erratics, as at Norber (north of Austwick), at the side, and in front of the ice depositing glacial sands and about half of this is within the scheme area, Limestone pavement. where huge blocks of Silurian sandstone were carried uphill by gravels (glaciofluvial deposits). In some cases, as at Trow Gill with examples occurring in many areas such Rocks For Us the ice moving south through Crummack Dale and deposited on Ingleborough, deep gorges were eroded by the meltwaters. as Scar Close on the side of Ingleborough. fascinating information about climate change, and their use by on the limestone at a higher elevation. Some blocks retarded Temporary post-glacial lakes also formed, as evidenced by the The economic geological resources of the Stories in Stone area both humans and animals. Bone remains from cave sediments the process of erosion of the limestone below and now sit on lake deposits on the very flat valley floors, and the shallow but Where vertical fissures have been enlarged larger depressions are very important and have a long history of use. Stone from small limestone plinths producing perched erratics. As the ice steep banks at what would have been the lake’s margins. called dolines are formed. Shakeholes or subsidence dolines in Victoria Cave have shown that during the Ipswichian field clearance or from small quarry pits was used to build the occur where a cover of soil or glacial deposits gradually interglacial period (around 120,000 years ago) when the familiar dry-stone walls and barns. Together with the many subside into the doline forming a small depression. These are climate was warmer, it was a hyena den with them feeding on buildings built from local stones they provide strong visual particularly well marked on the Ingleton side of the hippo, rhino, lion and elephant. The caves also provide the first clues to the local geology. The numerous disused limekilns Norber erratics - Photography by the British Geological Viaduct. Swallow holes or sinks are formed where streams flow evidence of humans in the area, around 12,500 years ago after provide evidence of lime being obtained, in the past for use in Survey/NERC into vertical fissures or dolines. As the water moves underground the last ice age. agriculture, from the Carboniferous limestones. Erratics are rocks which have been transported by glaciers from the joints and bedding planes which it follows may be enlarged At the surface, weathering (especially frost action) and erosion Four modern quarries, Arcow, Dry Rigg, Horton and Ingleton, their source region to their new location. The Norber erratics are through chemical weathering and may eventually form caves. of the limestone has produced extensive scree or talus slopes produce most of the crushed rock aggregate used in North a particular type called perched erratics, as the blocks of Silurian Within the Great Scar Limestone is a huge and complex cave Yorkshire, to build and maintain roads, housing, hospitals, beneath the limestone cliffs or scars. Austwick Sandstone Formation are resting on pedestals of system considered to be among the best in the UK. Many of factories and schools. . The upper surface of the pedestals was the the caves are of SSSI status and of European significance. The The majority of the karst landforms have formed on the Stories in Stone area has the largest concentration of caves in Providing newly exposed quarry faces, the active quarries are original rock surface after the ice had retreated, and the pedestals limestones of the Great Scar Limestone Group Malham the Yorkshire Dales National Park and includes the well-known also useful for scientific research and teaching. have been formed by the surface being lowered as a result of the Formation (particularly the Gordale Limestone) but others occur chemical weathering of the limestone (a process called dissolution). Gaping Gill (197 metres deep and 17 kilometres long). Held within on the Yoredale Group limestones. Many of the area’s numerous disused quarries are also To various degrees, the sandstone blocks have protected the the sediments and fossil passages is an unbroken sequence of important geological sites where rare rock units and features Photography by Hanson Heidleberg underlying limestone. The Austwick Sandstone blocks were eroded evidence for 600,000 years of landscape change. Stalactites With the exception of the reef limestones east of Settle, the may be seen, and several of them have been designated as Ingleton Quarry works the greywacke sandstones of the from crags, approximately 1km north in Crummack Dale, by a glacier and stalagmites (speleothems) have formed in the caves and South Craven and Middle Craven Faults generally mark the geological SSSIs or Local Geological Sites. that diverged from the main Ribblesdale glacier and flowed south- radiometric dating of the speleothems in the caves has indicated Precambrian Ingleton Group exposed in the Chapel le southern limit of the Great Scar Limestone in the area, and the We all benefit from the use of the natural resources, and great westwards into Crummack Dale and Norber. Recent dating of the at least three major phases of formation dated at approximately Dale section of the Craven Inliers. presence of the fault-lines creates dramatic variations in the efforts are made to fit our modern needs in with our use of Norber erratics has indicated that the ice retreated 19,000-18,000 350,000, 120,000 and during the last 13,000 years. scenery. More easily eroded shales to the south of the faults the countryside. years ago. These periods coincide with the major interglacials when surface have left a sharp southern edge to the limestone plateau, water was able to flow into the cave systems. Upon reaching an identified by a band of impressive scarp slopes and limestone impermeable rock layer the underground streams may appear cliffs including Warrendale Knotts and Attermire Scar near Photo © Tony Cooper at the surface as a spring or resurgence. Settle. The change in geology is also reflected in the composition The study of sediment deposited in caves has revealed of the dry-stone walls, and vegetation, across the fault-line. The very impressive 400 Trow Gill - Photo © Malcolm metre long Ribblehead Tebbit (cc-by-sa/2.0) Viaduct, built between 1870 and 1874, seen from Trow Gill is a most impressive the limestone pavement at gorge with 30 metre limestone Runscar Scar. The viaduct cliffs, which become even more crosses Batty Moss and impressive as the gorge narrows 8 metres of peat had to westwards from about 40 metres be removed to reach the to 3 metres. It was originally Great Scar Limestone assumed to be the product of bedrock. Yoredale Group the collapse of a cavern roof, but Hardraw Scar Limestone more recent evidence suggests quarried from Little Dale, it was formed by a powerful to the north, was used for meltwater flowing into Clapdale. its construction.

Doline types © Tony Waltham