Glaciation in Swaledale and Marske

It took hundreds of millions of years for the rocks that form the landscape in and around Swaledale, and therefore Marske, to form (see Geology, mining, and landscape page).  However, it is only in the last 100,000 years that that landscape has been shaped to what we see around us today.  The major force in this has been the work of glaciers.  The story of glaciation in Swaledale includes:

• ice sheets from the Lake District flowing to the east, and carrying pebbles from Shap, that missed Swaledale entirely;
• Swaledale and Wensleydale having their own independent ice-sheets;
• ice blocking the valley at Richmond, leading to the formation of the gorge there as shown in the nineteenth century painting below from Marske Edge;
• meltwaters forming possible lakes up Markse Beck and Arkengarthdale; and,
• rivers that carved the steep valleys on the north of the Swale. 

This page attempts to summarise some of the key features in Swaledale and around Markse that relate to glaciation – and in doing so cannot do justice to a significant amount of academic research. If you can add greater clarity or technical information please contact the webmaster, who would be only too pleased to hear from you. An instructive self-guided field trip to explore the glacial history of Swaledale around Keld and Muker has been published by the Yorkshire Geological Society¹.

The Swaledale landscape before glaciation

(See also Geology and mining page.)

Post-Carboniferous rocks?

In Swaledale there are no rocks younger than the Carboniferous (i.e. about 300 m years ago).  However the rocks we see today had been buried by up to 1.5km of younger rocks². Where did those rocks go?  The answer is that periods of mountain building in the Pennines led to them being eroded. 

Structural movements in the Pennines

After the Carboniferous period tectonic activity (movements of tectonic plates) led to the development of the 300km north-south crest of the Pennines, from the Peak District to the Scottish Border. 

The landscape of at the northern end of the Pennine chain is also defined by two major west-east structural features in the geology:  the Stainmore Trough (the A66 road corridor) and the Craven Faults (the A65 and Aire Valley corridor)^2,3. 

The Askrigg and Alston Blocks

The area between the Craven Faults (A65 road) and the Stainmore Trough (A66), including Wensleydale and Swaledale, is called the Askrigg Block.  The area north of Stainmore (A66) is called the Alston Block, including Teesdale and Weardale.  Both the Askrigg and Alston Blocks are defined by major fault systems and underlain by granite intrusions below the surface, the Wensleydale Pluton and North Pennine Batholith respectively³.  As granite is less dense than typical surrounding rocks over time it tends to rise into the terrain above leading to hills and mountains.  The 320+ million year-old Carbonifeous strata in these blocks, and which forms the visible geology of Swaledale, is tilted slightly from the Pennine crest to the east. At the eastern margins of the Pennines (e.g. at Richmond) these Carbonifeous rocks are buried by younger rocks in the Vale of York/Mowbray of Permian and Triassic age (c200 to 275 million years old).

To this day the land of the North Yorkshire Pennines in Swaledale and Wensleydale is higher than land north of it in the Stainmore Trough (“A66”).  Likewise, land in the Teesdale/Weardale Pennines is also higher than that in the Stainmore Trough.  A schematic map showing these features is shown below.

Erosion of younger rocks

The most recent episode of mountain building in the Pennines was about 20 million years ago, when the land of Britain became more elevated as the African and European tectonic plates collided to form the Alps².  The effect of this on central Europe was of course more dramatic (see photo of Alps below).

During these periods of mountain building the newest rocks would have been eroded first.  Hence well before the recent glaciations the Carboniferous rocks were left as the youngest rocks preserved in the area.  Perhaps those eroded rocks had included Jurassic sandstones like those that now dominate the North Yorks Moors, or Cretaceous chalk such as at Flamborough Head.  The remnants of such rocks now lie as sediments at the bottom of the North Sea.

Repetitive cycles of erosion³ are believed to have created the landscape in the Pennines where highest hills tend to be plateaus².  The broadly flat-lying nature of the underlying sedimentary strata of carboniferous rocks in Swaledale has probably accentuated this effect, in a way that is not so obvious in the Lake District where the underlying geology is more varied.

How long have the River Tees, Swale and Ure been around?

The main patterns of river drainage in the Pennines originated from about 60 million years ago, and well before the most recent period of glaciations set in (the “early Paleogene”).  This time coincided with the opening of the Atlantic Ocean³.  The Pennine drainage patterns were in turn influenced by the position of the structural blocks described above. The upper River Tees roughly follows the Stainmore Trough, and the Aire through Skipton and Leeds largely follows the Craven Faults. 

Between the Tees and the Aire lies roughly 60km of the Pennine chain.  As noted above the land is underlain by gently eastward dipping Carboniferous strata, forming a plateau dissected by rivers. The four principal rivers here are the Swale, Ure, Nidd and Wharfe.  Before these rivers reach the flat lands of the Vale of York, the Swale and the Ure flow in an easterly direction, whereas the Nidd and the Wharfe flow in a more south-easterly direction.  These river courses also exploited older fault patterns in the underlying carboniferous strata⁴.  Hence the Swale west of Reeth follows a long fault-line running west-east.  Further south where the Wharfe flows in a southern-easterly direction the dominant faults are also oriented from north-west to south-east.  The principal river valleys had become established well before glaciation set hold.

The last 2 million years.  Glaciation hits Swaledale.

Taken over the last 500 million years the glaciations of the last 2 million years are unusual both for Britain and the world as a whole.  Over the last 500 million years the earth was generally warmer, and the British Isles, through continental drift, was in equatorial and tropical latitudes for most of this period of time.  Most Britons have been trying to head south for their holidays ever since.  An animation showing Britain’s place in the world over time is here.

Milankovich cycles and glaciation

From about 2 million years ago (the beginning of the “Quaternary period”) the climate of the Northern hemisphere began to enter a period of dramatic oscillations, leading to periods of extreme cold and warmth.  The oscillations in climate are thought to be linked to natural wobbles in the rotation of the earth both on its own axis, and in its orbit around the sun (“Milankovich cycles”)².  These wobbles are caused by the way the orbit of the earth is influenced by the gravitational pull of the moon, Jupiter and Saturn – a great explanation is found on this YouTube clip.

Between 800,000 years ago and today there have been around 7 major cycles of glaciation, and a larger number of minor cycles³. Each period of glaciation coincided with the build-up of vast ice-sheets hundreds of metres thick, and a lowering of the sea level by up to 100m⁵.  The ice caps associated with these Pennine glaciations may have looked more like those seen today on plateaus in Iceland and Norway (see photo below).  The ice caps often extended across Scotland, the Lake District and North Yorkshire, and at times towards Southern England as well⁶.  Significant erosion took place primarily where the ice was moving.  Moving ice was also able to persist in valley bottoms for longer than it would have done had it been stationary. Where ice was stationary, including on the hill tops, little erosion took place. (Note work from the early twentieth century ^7,8 noted the lack of glacial deposits on hill tops and concluded that this was evidence that those hill tops were islands surrounded by the ice sheets (“Nunataks”). It is now beleived that this is not the case, and that the hilltops were covered with colder and stationary ice that caused little to no erosion⁶.)

Notwithstanding this the direct evidence of the earlier of these glaciations is sparse as each glaciation would have obliterated any traces left by its predecessor³.  The glacial effects we see around us today in Swaledale are largely the result of the very last glaciation².

The last glaciation.  Where was the ice in and around Swaledale?

Overview

The last glaciation was the most important as its imprint remains with us today.  This final period of glaciation took place from around 28 000 years ago to 15 000 years ago.  A huge amount of amazingly thorough recent academic work has been done to chronicle the “British-Irish Ice Sheet”, including producing time-lapse movies showing the position of ice every 1000-2000 years⁹. This web-page can’t do justice to the detail in that work.

In the north of England the last ice age was dominated by glaciers fed from mountain areas and higher land.  As already noted in the Pennines the areas of high land and the main valleys, including the Swale, had been established well before the onset of this final glaciation.  It was these features that determined (a) where ice accumulated, and (b) where and how it moved.  At the time of maximum glaciation in Swaledale the ice would have covered both the valley bottoms and all the hilltops.  In contrast the ice surface in the Lake District was between 800m and 870m above today’s sea level, leaving a few peaks poking above the ice³. 

Climate

The dominant climate during the “ice-age” was dry and arctic, and tundra-type vegetation would have dominated.  Mammoths, bison and woolly rhinos roamed Yorkshire⁵, although no such animal remains have yet been found in Swaledale!  (For the record this period is known as the Main Late Devensian glaciation³.) However the evidence also suggests that between periods of glaciation there would have been some shorter warmer periods.

Ice from the Lake District avoids Swaledale

One of the principal mountain areas feeding the largest ice sheets in the north of England was the Lake District, where harder volcanic and metamorphic rocks had withstood millennia of erosion to leave high and spiky peaks.  Much like Coast to Coast walkers carrying pebbles of red sandstone from St Bees Head to the North Sea (see coast to coast pages), these ice sheets from the Lake District carried distinctive stones with them eastwards (“erratics”), including pink Shap Granite.  Pieces of Shap Granite can be found along the Stainmore Trough (aka A66), the Greta Valley (e.g. in places such as Barningham or Gayles just north of Marske), within the Vale of York east of Richmond, and as far south as the Wash.  The most southerly piece in Swaledale is reported by Raistrick⁷ on the Marske-Richmond Road near to Park Top Farm, associated with the Feldom Morraine (see below).  These erratics are very significant as they indicate that ice from the Lake District, as well as that from the Eden Valley, North Pennines and Scotland passed all but the eastern end of Swaledale (and all of Wensleydale) on its way east⁷.  Other evidence such as the orientation of scratches (“striations”) in polished rock surfaces, and drumlins (elongate-shaped deposits of rocks and earth left by glaciers), points to these vast “Lake District/Cumbria” glaciers turning south into the Vale of York east of Richmond, avoiding the high ground of the North York Moors.  The ice from Cumbria effectively followed the line taken now by the A66 and A1 into the Vale of York³!

Swaledale and Wensleydale had their own ice sheet

Whilst ice from Cumbria was moving through the Stainmore gap (“A66”), both Swaledale and Wensleydale were filled by ice sheets fed from snow and ice accumulating on the local high ground at the head of the dales, as well as potentially from Mallerstang and the Howgill Fells¹¹.  Loose material was stripped from valley sides leaving the stepped pattern of harder bands of rock seen today in both Swaledale and Wensleydale². The glaciers laid down deposits on the valley sides and river bottoms, including boulder clays, moraines, and drumlins⁷. 

Impact of retreat of the Swaledale and Wensleydale glaciers on landscape

Most glacial deposits are associated with the retreat of glaciers. Around 20,000 years ago the glaciers in Swaledale and Wensleydale began to melt and recede.  Little seems to have been published about the glacial and post-glacial landforms specifically in Swaledale since a paper by Raistrick in 1927⁷.  These pages on the website are largely based on that work from 1927, augmented where by more recent work where relevant. Much more detailed and instructive work has been carried out more on glacial landforms in Teesdale, and this will have many similar characteristics to Swaledale in that the ice in Teesdale was also self-contained and locally derived, and hence not part of the regional Tees-Greta ice sheet that flowed from the Eden Valley and west¹².

The aim of what follows is to attempt to explain landscape features in the Marske area (and Swaledale) that may have a glacial origin. Prominent features are shown on the schematic map below.

In general the downstream parts of glaciers (the “snouts”) would have melted first.  It is likely that once the Swaledale glacier began to recede that its top surface would have remained initially above the hills, whilst the lower parts of the glacier in the valley bottoms would waste away with a snout that moved progressively in a westwards direction. Once the self-contained Swaledale ice began to melt then perhaps the Marske-Richmond part of the confined Swale valley was the first piece of land to be uncovered, leaving tributary glaciers in Marske Beck and the Swale valley towards Reeth. There is evidence (see below) that in retreat the Swale ice then paused also in the Marrick area, and then again towards Low Row.

Melting glaciers produce a lot of water!  Meltwater usually finds channels under the glacier or around its edges; it can also flow on top of the glacier.  Given the high volumes of water involved the erosion caused by glacial meltwater can be very significant.  Channels of water also create deposits of boulders (often rounded), gravel and sand. The sand and gravel deposits east of Richmond in the Vale of Mowbray (e.g. near Brompton on Swale and south from there) are the result of this¹³. Where the flows of water are temporarily blocked, either by ice, rock or rocky deposits, lakes can form. Lakes leave deposits of clays, sometimes showing fine patterns reflecting yearly cycles, and sometimes containing isolated stones that have dropped into the clay from floating bergs.  Any of these deposits can then be eroded by the final actions of the glacial retreat.  Local features of the landscape that may be explained by glaciers, and their retreat, are described below.

Impact of glaciation on the Swale valley between Marske and Richmond

The upper Swale (i.e. that part of the Swale upstream of Richmond) is unusual in that the valley is narrowest in its downstream section between Richmond and Downholme Bridge (the bridge to Marske over the Swale).  The section near Richmond itself is a small gorge.  In contrast Wensleydale (the Ure valley) has a more classic profile than the Swale, widening progressively along its length. 

The most likely explanation for this is that the Swaledale ice may have been blocked near Richmond by the bigger ice flows that had emanated in the Lake District and Southern Scotland (“Tees-Greta ice”) and whose flow turned southwards around Richmond^7,3,14.  Raistrick goes on to suggest that the two “right-angled bends” in the Swale valley, roughly a kilometre either side of the confluence with Marske Beck, may have exacerbated any “jamming of ice in the [Swale] valley” west of Richmond.  The eastern end of the Swale valley at Richmond also coincides with outcrops at the surface of the hard Richmond Chert beds, which dip gently east from their higher elevations on the hill tops around Marske and Downholme⁴.  These outcrops of harder rocks at Richmond may also have constricted the flow of the Swaledale ice further.  Recent work suggests that the Tees-Greta ice sheet, which was flowing eastwards through the Stainmore Trough, receded about 20,000 years ago, whereas the Swaledale and Wensleydale ice persisted for another 2000-3000 years^14,9. Hence for a short period the Swaledale ice was unconstrained by the bigger ice sheet and may have flowed more quickly through the Richmond area in the direction of Brompton and the Vale of Mowbray before it too began to melt and recede. If that had been the case that quickly flowing pulse of Swaledale ice over those 2000-3000 years may have scoured the small gorge we now see today at Richmond. The schematic map below illustrates this hypothesis.

The continual draining of the Upper Swale valley, after the ice had receded from Richmond, may have been associated with continued erosion of the river channel.  It could have been at this time that the river Swale cut itself a new channel that by-passed the meander at Round Howe, and which led to the river level falling from 135m to 105m.  The satellite photo compares the old course of the Swale with the current course taken at Round Howe.

Round Howe is very difficult to photograph, but an early nineteenth century painting by George Cuitt illustrates the feature better than any modern photograph can. (At that time there was a temple on top of Round Howe, that Temple has long gone.)

Raistrick also points out a shallow valley along Victoria Road at about 135m in Richmond.  This, and/or the area of the Market Place, might have been a previous course of the Swale, before the channel was cut that carries the river south of the Castle today⁷. 

Significant moraines (mounds of rocks) left by glaciation in Swaledale and Wensleydale

Retreating glaciers also leave a lot of debris mounds, including rocky “moraine” deposits both at the edges of ice sheets, and at the ends of ice sheets (“snouts”) as they have melted and receded.  Raistrick’s study of glaciation in Swaledale and Wensleydale maps many of these features⁷.  Several prominent moraines, each with a different explanation, are set out below. A better, and more recently studied, examples of debris mounds and their glacial origins is provided work in Teesdale¹².

Feldom Moraine

One of the most prominent rocky deposits in the area is the “Feldom moraine”.  This narrow ridge-like feature, with a relief of up to 10m, extends over a length of nearly 10km from Feldom Moor near the army building on Feldom Lane, north-westwards via Stone Man Cairn, towards Byers Hill Farm on the Marske-Newsham Road north of Marske.  The Google Map satellite view (below) shows this clearly as a snake-shaped sliver in the centre of the area. 

Raistrick and more recent researchers have recorded that this moraine marks southern edge of the “Teesdale-Greta” Ice, and that its sharp contours and steep sides suggest the moraine formed very late during the last glaciation^7,14.  This hypothesis is further supported by the finding of an erratic of Shap granite near the southern end of this feature, and deposits that indicate small lakes dammed to their north by this feature.  To note however that others have separately attributed the Feldom moraine as an esker – a deposit left by water flowing underneath a glacier¹⁵.   

Moraines between Bellerby and Halfpenny House

Raistrick also observed several west-east moraine ridges in the area between Bellerby, Halfpenny House and Catterick Camp⁷.  Some of these ridges can be seen from the main road (A6108) between Halfpenny House and Bellerby; others are within the MoD land.  Raistrick interprets these ridges as having been deposited on the “lateral” edges of the retreating Wensleydale ice sheet. Much of the drainage in this area runs west to east, and not directly down the natural slope of Wensleydale towards Bellerby and Leyburn.

Drumlins and End Moraines between Marrick and Healaugh

Both Wensleydale and Swaledale have drumlins.  These are shaped mounds of rock and earth that formed beneath ice sheets, and which typically have a lengthened shape in the direction of ice movement.  In Swaledale Raistrick notes the main area of drumlins are between Muker and Gunnerside (he notes that it can be difficult in Swaledale to distinguish drumlins from lateral moraines formed at the edges of the ice sheet). 

Raistrick also notes that three moraines in the valley bottom in Swaledale may record the sequential positions of the “snouts” of the ice sheet as it receded.  These are (1) just west of Marrick, (2) a larger deposit at Grinton (Ewelop Hill – see photo) which rises 20m above the valley bottom there, and (3) a small moraine between Healaugh and Feetham (How Hill).  Maps in more recent articles reflect this understanding¹⁶. These three terminal moraines are correlated with river terraces, also related to pauses in the retreat of the ice.  In Swaledale Raistrick notes three terraces in the Swale below the Marrick moraine, two between Marrick and Grinton, and one between Grinton and Healaugh.  The current river level of the Swale, which is below the lowest of these terraces, is explained through the continued down-cutting of the river against the backdrop of the uplift of the north of England associated with “glacial rebound” (after the removal of up to 1km of ice after the ice age the earth’s crust rose up slightly across the north of Britain.).

Erratics

As well as larger linear moraine deposits the ice also left isolated boulders, termed erratics (the Shap granite boulders mentioned earlier are also examples of this).  One example of a glacial erratic is found on the moor near Marske between Cordilleras and Orgate, and like almost all erratics in Swaledale it is of local origin¹⁷.  Many erratics that were left by glaciers were cleared by early farmers as land was enclosed into fields, and they are occasionally found in some of the older stone walls in the area.

Formation of steep-sided Marske Beck – from meltwaters draining from the Tees/Greta ice?

Raistrick proposed meltwater lakes on the southern boundary of the Greta-Tees ice on the upper slopes of the Greta valley between Bowes and Dalton, and at around 385m and 360m.  He proposes that these lakes flowed over into Swaledale via the Mud Beck channel (at c385m) high in Arkengarthdale, and via the Harker Moss and Snaiza Gill channels (both at c360m) at the head of Rake Beck, leading to Marske Beck.  He describes the Harker Moss channel as being “enormous” and infers that it would have been an active escape channel for the lake waters for a considerable time.  He attributes the steep-sidedness of Marske Beck to the erosion caused by these meltwaters. 

Raistrick also describes the steep-sided mini-gorge of Deepdale (between Marske and Richmond on the north of the Swale) as being caused by “ice edge drainage” linked to water channelled on the southern edge of the Feldom Rigg. One wonders if the position of Feldom Rigg more generally controlled the flow of water (from the edge of the melting Tees-Greta ice-sheet?) to each of Marske Beck/Throstle Gill, Clapgate and Deepdale at various times and in such a way that they all developed quite as steep-sided valleys.

Unstable valley slopes

A further legacy of the glacial retreat, especially on steeper valley sides including Marske Beck, is the instability of “over-steepened” slopes alongside the becks.  In the Marske Beck area three areas of unstable slopes include (i) the extensive area of hummocky ground below the cliffs at Clints Scar and Orgate, (ii) a large area of “rotational slip” in the slopes south of Skelton Farm on Stepping Gill (thanks to Local Contributor 4 for pointing out this feature), and (iii) soil-slip in many locations, but most recently in the last five years, near the Packhorse Bridge near Orgate Farm (for general information on Clints see here.). The area of hummocky ground above Orgate is almost 1 km in length and includes large numbers of sizeable blocks from the cliffs above, often at some distance from the cliff edge, and at least one very large block of about 10m in length distant from the cliff edge.

Glacial lakes over Reeth, Marske and Downholme

Raistrick proposed that the waters that flowed into upper Arkengarthdale and Marske Beck formed a lake covering upper Swaledale to the ice choked in the Richmond gorge (“The Arkengarthdale lake”).  Such a lake could have extended west to Muker or Thwaite when it was at its highest level.  Raistrick suggested in the Marske Beck valley this glacial lake has shorelines consecutively at 315m and 267m. He deduced these shorelines by assuming (a) that Swale glacier did indeed block the eastern end of the valley at Richmond, (b) that lake levels were determined by the topography in the present-day landscape, and (c) that the primary drainage from these lakes would have been along Swaledale – potentially along the northern edge of the glacier.  As the glacier receded, and the lake levels became lower, Raistrick suggests shorelines along the Swale valley west of Richmond towards Marske/ Downholme of consecutively of 238m, 162m and 131m based on successive likely escape routes for lake water/meltwater. 

Whilst speculative the flat lands south of Telfit may also have been sites of short-lived glacial lakes. 

An alternative route for the Swale?

An alternative hypothesis is that any extensive lakes covering Arkengarthdale and the Marske Beck area, might alternately have drained through the gap between Swaledale and Wensleydale where the current Richmond-Leyburn Road (A6108) crosses the watershed in the vicinity of Halfpenny House.  This would also have created a shoreline at around 240m.  If this were the case the River Swale, with at least one lake along its course, would have flowed down the valley now occupied by Bellerby Beck and Newton Beck towards Bedale, rather than flowing through Richmond as it does today.

As an aside until the end of glaciation the Tees, east of Barnard Castle, had flowed via Holmedale and Skeeby Beck into the Swale¹².

Gaining confidence in the “Lake Arkengarthdale” theory.

Raistrick’s work, which dates from 1927, is detailed and carefully thought through, however it relies on hypotheses around where lakes might have formed based largely on his wider understanding of the timing of glacial retreat, and the contours of the land where lakes might have formed.  Many deposits left by such lakes might have now been subsequently eroded, but where such deposits are to be found they would further support his proposals.  One observation that may indicate the position of an old lake shore is a possible delta on the 200m contour line near Stainton.  Our confidence in the proposals that such lakes did exist would be strengthened by more observations of phenomena that might be associated with old shorelines, or with deposits of unambiguously identified lake clays in the valleys. 

Clays

In many areas around Marske there are deposits, in some places up to 40 feet thick¹⁸, of a sticky pure blue clay.  Near Marske itself, at about the 165m contour in Marske, there is clay (i) at the site depicted on the 1854 map as Tile Pits east of the village, (ii) encountered by grave-diggers in the small cemetery in the village, and (iii) at sites where a garden pond has been dug recently.  The blue clays sometimes contain smooth singular stones, which could have been dropstones deposited from ice rafts floating over any glacial lakes.  At Marske the old clay pits were used in the nineteenth century to create pipes for land drains, that often were used to drain the very land on which the clay had been deposited (see pages on farming).  The origin of these clays is unclear, but they could have formed in lakes at the time of recession of the ice sheets. 

Go to geology, mining and landscape page.

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7. Raistrick, Arthur.  1927.  The glaciation of Wensleydale, Swaledale and adjoining parts of the Pennines.  Proceedings of the Yorkshire Geological Society.  Vol 20.[↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩][↩]
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10. Local Contributor 16. 2024. Extract from database.[↩]
11. Davies, B.J. et al 2019. Dynamic ice stream retreat in the central sector of the last British-Irish Ice Sheet. Quarternery Science Reviews.[↩]
12. Evans, D.J.A., et al. 2018. Glacial geomorphology of Teesdale, northern Pennines, England: Implications for upland styles of ice stream operation and deglaciation in the British-Irish Ice Sheet. Proceedings of the Geologists’ Association.[↩][↩][↩]
13. Bridgeland, D.R. et al. 2011. Late Quaternary Landscape Evolution of the Swale-Ure Washlands, North Yorkshire. Oxbow Books[↩]
14. Davies, B.J. et al 2019. Dynamic ice stream retreat in the central sector of the last British-Irish Ice Sheet. Quarternary Science Reviews.[↩][↩][↩][↩]
15. Britice 2017, BRITICE Glacial Map v2.0, University of Sheffield[↩]
16. Davies, B.J. et al 2019. Dynamic ice stream retreat in the central sector of the last British-Irish Ice Sheet. Quarternary Science Reviews.[↩]
17. Local Contributor 16. 2024.[↩]
18. Local Contributor 4, 2023[↩]