11 This is another great view. The valley follows the Llanbadoc fault, but here that’s not the edge of the inlier. At the end of the field walk straight down through The Llanbadoc Geology Trail the farm yard(beware tractors), then turn left on The trail can be walked from Maryport carpark in Usk, Cefn Ila the lane and take the first path on the right down Woodland Trust car park or Llanbadoc Island car park. The trail is to the bat house of the Woodland Trust’s Cefn Ila. on public footpaths which can be slippery and rough underfoot so stout footwear is essential. There are 2 ups and downs of moderate steepness. Do not approach high quarry faces as they Space for qr code and logos. 8 The house is long gone ( did you spot the bricks on the are mostly unstable and trees or rock could fall and seriously We are looking North. The centre of our This is brilliant. track?)but there are the remains of the walled garden the injure you. The whole trail is 6.4km or 4miles and will take 3-4 dome is around Monkswood, just to the Behind Llancaeo lake and even the old garden terrace in the trees. There is a hours, but there are a couple of short cuts . The Llanbadoc-Usk Need a better fossil photo fine arboretum. To add to the romance ,the original owner left(West) of the prominent line of black mill there is a row part could be walked and you could drive to Cefn Ila to walk that poplars. But there is a ridge North of of wooded hills was a friend of Shelley and brought seedlings from Shelley’s part of the trail separately. grave to grow here in his garden…….. Monkswood which is nothing to do with the running down the Take water or better still a picnic with you. dome. It is the material dumped by the Usk side of the Usk There is an exposure of the Upper Llanbadoc beds on the Some of the stiles are dog unfriendly, those in Cefn Ila are not. Glacier at the end of the last ice age and valley towards us. drive. They are thin beds of mudstones and wider ones of fine sandstone, dipping to the South East as expected. marks the Southerly edge of the last ice Have a look at the sheet 20,000years ago. It is called a map and you will There are fewer fossils in these, but they are very different to the rocks we will see next. moraine. see they are topped by our old

1 1 1 tough friend the 1 2 4 1 1 0 3 Carry on down the drive and take the gravelled path on the right. blue Llanbadoc P beds. You may spot Go straight on at the crossroads of the paths and walk about 50 6 Usk castle as the 7 5 4 yards. Opposite the tubular bells is an exposure of the Usk last one appears. limestone. Go over to the pile of loose stones near the exposure 9 8

3 1 The beech 5 P tree likes a

limey soil. 2 1 Watch out! You are about to cross the Rhadyr fault again. The 12 loose stones at the edge of this next field often contain fossils. Pic of the exposure Continue along the trees , into the next field, turn right up the lane, then left before the gate and go straight down by the hedge until you come to another stile. There is an

enormous beech tree on your left. Carefully walk up to the shortcuts right of it as just beyond it is a quarry in the lower Llanbadoc beds. 13 Cross the stile now . Walk across straight ahead to the fossils There are lots of loose next field. Ignore the farmer’s track.Then cross the stile fragments to look at. DO NOT We hope this trail gives you some idea of the geology into the next field, walk through the centre of this field to another stile and walk up by the hedge on your right GO NEAR THE FACE, but if you of the Earth under your feet, and how geologists are look from a distance you will (North) like detectives who put together the evidence and notice a band of lumpier rock 7 about a metre from the clues to build a picture of the history of the whole 9 bottom. This is a more planet. From this field there is a great view on your left of the The Usk Limestone.The rocks look orangey and concentrated limestone band South part of the inlier. It doesn’t look much like a dome . are rough, knobbly and hard. Use the brushes to brush where the limestone has This is because the centre of the dome has the oldest rocks the dust off and have a careful look. This is the remains of The trail starts in Llanbadoc car park because geology formed hard nodules. but they are some of the softest. Some of the outer rocks a coral reef full of fossil sea lily pieces, corals, bryozoan really owes a great debt to a man who was born in a Llanbadoc beds) form the wooded ridges . bits along with some braciopods and trilobites.They are house close by, Alfred Russell Wallace. The long ridge of Wentwood to the East is of a tough older than the mudstones we have seen so far. It was Continue on the path down left roughly parallel to the stream. sandstone part of the ORS. It is not part of the dome but it formed in shallower water that was still and clear. It was Cross the stile ignoring the footbridge on your right. The next stile was folded up by the same movements. The ridge of the quarried here for use on fields or for mortar. It is far older crosses a footbridge into a field. Walk by the hedge, right, to the coalfield in the West was also folded, but folded than the carboniferous limestone of the Wye Valley or the path on the right before the houses. It leads to the main road. He became a Cross carefully and turn right up the steps by the brown sign. Walk downwards into a basin so younger rocks called coalfield. famous naturalist and co- Carboniferous rocks (360- 350Milliion years old ) form the past the children’s playground along the river. Take the pink path 14 and you can finally see the Old red sandstone – in the bridge. Now proposer (with Darwin) of top of the ridge but the lower part is ORS again. ORS has Retrace your steps to the junction of paths and take the first left at the bridge you can stop for refreshment or visit the Rural life the theory of Natural us surrounded. up the hill. Walk up to the next 2 stiles that cross the track. Cross museum in Usk, before returning back over the bridge( be very Selection, the mechanism them both and walk ahead to the closest clump of trees careful crossing the road) walking by the river on the flood of evolution. Wentwood Ty’n y caeau Coalfield opposite. The stile you can see to the right is another short cut to defences back to Llanbadoc. ORS Silurian ORS lowest slopes get back to Llanbadoc. Our next stile is hidden in the trees . Walk to the fence as its less steep to walk to the stile this way. Cross. 15 Darwin noticed that small differences between species 10 You have just crossed the Cefn Ila fault. Ahead, it runs in the hollow Nearly back where we started,stop by allowed some to survive better than others in different to the left of the stile. Behind you,it runs down through Cefn Ila just the bench. There is a house under the steep cliffs. conditions. Wallace added that species varied even if the to the right (West) of the track below the bat house. This was Wallace’s house. The bench is dedicated conditions were identical if a physical barrier isolated them to Wallace, and a little further on there is a from each other. So if a new physical barrier developed then the same species would evolve differently in the now memorial stone outside the church. Wallace was Continue on the path through the trees, take the left fascinated by the Natural World and we hope that separated areas. path to the next stile into an open field below the line our journey through continental collisions to coral of the trees . Stop about half way along when you can seas, desert plains and an ice age all in the space of Very few children in Usk had stones in their gardens that were see both the Sugar-loaf on the left (West)and Llancayo an afternoon is a fitting tribute. full of fossil shells as Wallace did. We can only guess how it windmill on the right (East). influenced him or how thrilled he might have been that he The view from 7 looking South contributed to the theories explaining why those shells were in Copyrights missing those rocks. Continue up the footpath onto the top of the cliff, past When high ground is weathered, rock is broken down to mostly the gate where the path turns sharply up and cross the As you walk up to the last stile, first The Skirrid pops sand and mud and deposited by wind or water to form new next stile. We are now on a level set of long fields. Keep into view ( Old Red Sandstone), then a little further, sedimentary rocks. Small changes in conditions can lead to The Usk Inlier the Sugar loaf (ORS) which looks like a volcano but isn’t, separate flat bands of rocks called beds to be laid down on top of to the right (East)side of the fields .Through the trees Then, if clear enough, Waun Fach (ORS). each other like a pack of cards, the oldest being at the bottom. you can see Usk on the other river bank far below . Go These sediments and any plant or animal remains( fossils) get straight ahead through 2 more stiles. buried deeply ( at least 1.5km) and the water is squeezed out to form new rock. Sometimes it may be brought back up to the Old Red Sandstone Lots of clues in geology come from the types 4 surface by movements of gigantic pieces of the Earth’s crust, Upper Llanbadoc and Llangybi beds called plates, which crash into each other swallowing oceans and Lower Llangybi beds of soil and loose stones we can see, and the Forest beds For the shorter route. Carry straight on .You will pass a stile thrusting mountains up, or rift apart to create new basins and Usk limestone pattern of the land. These long fields have Ton Siltstone 3 fertile soils and steep drops either side…. heading down the cliff but this path is very steep.so ignore this oceans. LOOK across the river. These rocks have weathered mudstone and carry straiht on until you come to the next stile . quickly and form the level ground of the East bank. Then look Cross this stile, and you will pass an old limestone quarry on the behind you and see the higher, hilly ground leading to the high RIGHT. Do not go near the faces. cliff running up to Usk . Monkswood Why is this side so different? F S The beds here are the lower Llanbadoc beds which Llanbadoc A h have more limestones than the upper beds. They seem o flat but if you move past the exposure and look back, U Rhadyr r they are actually quite tilted. Geologists need to be L If you look at the geological map, you will see an irregular oval Usk t careful observers. You may also notice a lot of holes in 8 1 T the faces as if the rock has been dissolved away. It Has. with blue rings, cut off at a slant at the top. This is the Usk Inlier, a SILURIAN 4 Cefn Ila e Cefn Ila Limestone is slowly dissolved by rainwater, even though dome of older Silurian rocks pushed up higher than the younger INLIER S r Old Red Sandstone ones, then the top is worn away to reveal the its tough. Look across at Usk Castle. It is on another slice older rocks in rings, oldest in the centre. We are on the South Llanbadoc r of the inlier on the Lower Llanbadoc .Take the path now Eastern edge of the dome. 1 o down into Usk. Join the route after crossing the footbridge, turn right over the second footbridge into u the field. Follow the right hedge to the houses and the The Silurian rocks were laid down IN THE SEA and form a series of Coed-y-Paen t road. beds of deeper water mudstones containing shelly fossils, e tougher limestones where there is enough lime to act as cement, and shallow water tough sandstones. The oldest rocks in the Pici? dome ( 430 million years old) are soft mudstones and form Llangybi THE BLACK slightly lower ground. The limestones and sandstones are harder ORS DASH LINES and protect the rocks below from being worn down so they form ORS ON THE MAP ridges of higher ground. These form the cliff opposite. MARK FAULTS

LOOK at the rocks on your right. Are the beds here 5 For the longer route, after the stile, walk 2 flat? These are the Silurian rocks and are OLDER than the around the left hedge to the Western edge of ones on the other side of the river ,even though those To your right is a fault , called the Llanbadoc the field until you come to the next stile. Cross younger rocks are now lower. There is some loose material fault. You also stand on it in the car park by the it . Look to your right before crossing the next which contains fossils. These rocks are mudstones with some lime cement called the Upper Llanbadoc beds (grey information board). A fault is a deep crack in the stile. earth where rocks have slid against each other. What’s up? blue on the map) and have been tilted up steeply by huge forces. They formed before the old red Sandstone in a When the dome of the Usk inlier got pushed up, rapidly filling sea, getting less muddy and more sandy 350million years ago, the rocks got folded and towards the top as they were becoming land, as two The Inlier continents , Avalonia and Laurentia(which held Scotland), squashed upwards, but 100 million years later slid together and squeezed out the sea. when Pangea was breaking up, It cracked a bit The range of fossils found in these beds , called a fauna like slicing a cake. Then more movements jostled allowed geologists to work out the rock’s age compared to the pieces up and down so that the different 1 The rock s on the other side of the river are covered up by other rocks both above and below them but also compared bands of rocks occur next to each other, more modern sediments including those from river to those in other parts of the world. So Avalonia (here) used flooding. Beneath them lies thin flaky reddish soft to have a different fauna of fossils from Scotland (on bounded here by a series of almost parallel mudstones of the early part of the Old red Sandstone Laurentia) until they collided then they mixed and evolved North-South running faults. Because the rock has (ORS). These were laid down 420 million years ago , to be more and more alike. This helps work out where been broken along the fault it often weathers ON LAND in a hot dry climate on mud flats or shallow different continents were, and when they collided. THANKS ALFRED more quickly, especially if a large river like the lakes. We were on a continent known internationally as Usk finds it. Avalonia, (named after Avalon Newfoundland, itself named after King Arthur’s mystical land which curiously enough For a piece of continent, this patch has been busy. was first mentioned by local boy Geoffrey of Monmouth in The Radyr fault lies to the right of the track 1136). These ORS rocks contain few fossils . They are the Pic Avalonia and Laurentia? Fossil pics youngest rocks of our trail and cover a large part of from the edge of the Coalfield to the West, Fossil pics These long fields run between two faults, the to Wentwood in the East and beyond.. Llanbadoc and the Radyr fault. We will meet them again. Turn left out of the carpark. Walk up to the main road by the church, turn right and and cross by the These rocks were buried but weren’t folded into the dome So these shelly rocks were in Alfred for another 100 million years when another continent church tower, when you have the best sight of the Russell Wallace’s garden smashed (at 2 cm a year)into our new continent from the 6 For the longer short cut, take the path by the right road in both directions. Take GREAT CARE, look and South to make a supercontinent called Pangea. because………………. hedge above the trees. Carry straight on this line listen. Take the footpath signposted up the bank, 1 his house is on this side of the river. and join the trail at 0 . It bypasses Cefn Ila . then stop. Croeso i Ddyffryn hardd afon Wysg lle y dylai ' r Afon redeg ar orlifdir llydan gwastad. Ond Welcome to the beautiful Usk Valley where The Usk Inlier nid hynny sy wedi digwydd oherwydd ar yr the river should run on a flat broad flood ochr hon mae clogwyn mawr a thir uwch. plain. Except on this side there is a large cliff Old Red Sandstone Mae fel petai ' r Afon yn taro i mewn i and higher ground. It is as if the river bumped Upper Llanbadoc and Llangybi rywbeth ac yn dod o hyd i ffordd o gwmpas yr Lower Llangybi ochr. into something and found a way around the Forest beds Penperlleni side. Usk limestone Pam mae ' r ochr hon mor wahanol? Why is this side so different? Ton Siltstone Glascoed mudstone Pan fydd tir uchel wedi ' i hindreulio, mae ‘ torri I lawr i dywod a mwd yn bennaf a ' i dyddodi gan wynt neu ddŵr Brynbuga When high ground is weathered, rock is boken down to i ffurfio creigiau gwaddodol newydd. ar dir neu yn y môr. Usk mostly sand and mud and deposited by wind or water to Gall newidiadau bach mewn amodau arwain at fandiau form new sedimentary rocks, on land or in the sea. Small fflat -gwelyau wedi gosod un ar ben y llall,, rhai hynaf ar y changes in conditions can lead to separate flat bands of gwaelod. Mae ' r gwaddodion hyn ac unrhyw weddillion planhigion neu anifeiliaid (ffosiliau) yn cael eu claddu ' n rocks called beds to be laid down on top of one another, Llanbadoc Rhufeinig yma the oldest being at the bottom. These sediments and any enw yr ardal ddwfn (o leiaf 1.5 km) ac mae ' r dŵr yn cael ei wasgu allan i ffurfio Craig newydd. Weithiau gall gael ei ddwyn plant or animal remains( fossils) get buried deeply ( at SILURESdrigolion yn ôl i fyny i ' r wyneb drwy symudiadau o ddarnau least 1.5km) and the water is squeezed out to form rock. Coed-y-Paen Am hen Sometimes it may get brought back up to the surface by Llangybi enfawr o gramen y ddaear, o ' r enw platiau, sy ‘ n taro i ' movements of gigantic pieces of the Earth’s crust, called w gilydd gan lyncu cefnforoedd a chodi mynyddoedd i plates, which crash into each other swallowing oceans Silurian CREIGIAU COCH fyny, neu torri ar wahân i greu basnau a cefnforoedd the SILURES and thrusting mountains up, or rift apart to create new Mae ' r graig ar ochr arall yr newydd. - named after a Welsh tribe afon wedi ' i gorchuddio gan Mesurir oedran y creigiau hyn mewn miliynau o basins and oceans. waddodion mwy modern gan flynyddoedd ond pan welir newidiadau mawr yn y The Age of these rocks is measured in millions of years gynnwys y rhai o’r afon sy ' n gorlifo. Oddi tano mae haenau creigiau Mae ' r cyfnodau amser yn cael enwau hefyd. but when big changes in the rocks are seen the time o gerrig llaid meddal o’r periods are given names too. ddechrau’r adeg hen dywodfaen coch (ORS). Gosodwyd y rhain i lawr RED ROCKS 420,000,000 mlynedd yn ôl, ar dir, mewn hinsawdd sych a The rock across the river is covered up by more modern sediments including those from the river flooding. Beneath them lies thin flaky phoeth ar fflatiau mwd neu reddish soft mudstones of the early part of the Old red Sandstone (ORS). These were laid down 420 million years ago , ON LAND in a hot lynnoedd bas.Mae rhain yn Gallwch gerdded o Maryport, maes parcio ym Mrynbuga, maes parcio dry climate on mud flats or shallow lakes. These are younger than the ones of the higher ground in front????of you. How do the older ifancach na’r rhai o’ch blaen. rocks come to be higher up? Ymddiriedolaeth Coed Cadw Cefn Ila neu faes parcio yma. Mae'r llwybr ar Sut mae’nhw’n is? lwybrau cyhoeddus a all fod yn llithrig o dan draed felly mae esgidiau The Usk Inlier cryf yn hanfodol. Peidiwch a mynd yn agos i wynebau chwarel uchel gan Mewnle Brynbuga eu bod yn ansefydlog ar y cyfan a gallai coed neu graig ddisgyn a'ch If you look at the geological map, you will Os edrychwch ar y map daearegol, byddwch yn anafu'n ddifrifol. Mae'r llwybr cyfan yn 6km neu 3.75 milltir a bydd yn see an irregular oval with blue rings, cut off gweld ofal afreolaidd gyda cylchau glas, wedi ' u cymryd 3 awr, ond mae cwpl o doriadau byr. Neu gellid cerdded rhan at a slant at the top. This is the Usk Inlier, torri i ffwrdd ar ogwydd ar y top. Dyma ' r Inlier Llanbadog-Wysg a gallech yrru i Cefn Ila i gerdded y rhan honno o'r llwybr where the flat rocks have been pushed up Wysg, lle mae ' r creigiau gwastad wedi cael eu ar wahân. into a dome, then the top has been worn gwthio i fyny i gromen, yna mae ‘ r pen wedi ei shortcuts away to reveal the older rocks in rings, hindreulio i ffwrdd i ddatgelu ' r creigiau hŷn oldest in the centre. These Silurian rocks mewn cylchoedd, hynaf yn y canol. Mae ' r are pushed up higher than the younger Old creigiau Silwraidd hyn yn cael eu gwthio i fyny Red Sandstone ones that surround them. yn uwch na ' r hen dywodfaen coch iau sydd o ' They were laid down IN THE SEA and Very few children in Usk had stones in their Cafodd Alfred Russel Wallace, naturiaethwr a chyd- u cwmpas. gardens that were full of fossil shells as Wallace gynigydd enwog (gyda Darwin) o ddamcaniaeth form a series of beds of soft deeper did. We can only guess how it influenced him or dethol naturiol, mecanwaith esblygiad, ei eni yn Cawsant eu gosod i lawr yn y môr ac how thrilled he might have been that he Llanbadog. water mudstones containing shelly contributed to the theories explaining why those Ychydig iawn o blant ym Mrynbuga oedd â cherrig maent yn ffurfio cyfres o welyau o gerrig fossils, tougher limestones where shells were in those rocks. Alfred Russel Wallace,a llawn o ffosilau gregyn yn ei gerddi, fel oedd yng famous naturalist and co-proposer (with Darwin) ngardd Wallace. Ni allwn ond dyfalu sut llaid meddal , calchfaen lle mae digon o there is enough lime to act as cement, of the theory of Natural Selection, the mechanism dylanwadodd arno neu pa mor falch y gallai fod I of evolution, was born close-by. wybod bod o wedi cyfrannu at y damcaniaethau galch i weithredu fel sment, a cherrig and shallow water tough sandstones. esbonio pam yr oedd y cregyn hynny yn yr ardd. tywod caled dŵr bas. The oldest rocks in the dome happen to be Mae ' r creigiau hynaf yn y dôm yn digwydd bod soft mudstones and form generally lower yn gerrig llaid meddal ac yn ffurfio tir is yn y ground. The sandstones and limestones are canol. Mae ' r tywodfeini a ‘ r calchfaen yn The geotrail can be walked from Maryport carpark in Usk, Cefn Ila harder and protect the rocks below from galetach ac yn amddiffyn y creigiau islaw rhag Woodland Trust car park or Llanbadoc Island carpark. The trail is on being eroded so they form ridges of higher cael eu herydu ,felly maen nhw ' n ffurfio cribau public footpaths which can be slippery and rough underfoot so stout ground like a rim. These form the cliff which o dir uwch. Mae rhain yn ffurfio ' r clogwyn a footwear is essential. Do not approach high quarry faces as they are was quarried for its limestone. gloddiwyd am ei galchfaen. mostly unstable and trees or rock could fall and seriously injure you. The change in level is made more dramatic Mae ' r newid yn y lefel yn cael ei wneud yn The whole trail is 6km or 3.75miles and will take 3 hours, but there because there is a crack, a fault running fwy dramatig oherwydd mae crac, ffawt yn are a couple of short cuts . Or the Llanbadoc-Usk part could be along the river. It throws the land to the Fossil pics rhedeg ar hyd yr afon. Mae ' n taflu ' r tir i’ r walked and you could drive to Cefn Ila to walk that part of the trail East across the river downwards and it is a dwyrain ar draws yr afon tuag yn is, ac mae ' n separately. line of weakness where the has llinell o wendid lle mae afon Wysg wedi erydu’r cut back the broken rocks leaving a steep creigiau toredig gan adael clogwyn serth. cliff. Need copyrights