Gurreholmsdal ice retreat stages and advances

Moraine ridges and other morainic features in Gurreholmsdal, identified by Kelly et al.

Moraines and sample locations

"A 10 Be chronology of lateglacial and Holocene mountain glaciation in the Scoresby Sund region, East Greenland: implications for seasonality during lateglacial time." 
Meredith A. Kelly et al, 2007.
Quaternary Science Reviews xxx (2008) 1–10

https://www.academia.edu/18196712/A_10Be_chronology_of_lateglacial_and_Holocene_mountain_glaciation_in_the_Scoresby_Sund_region_east_Greenland_implications_for_seasonality_during_lateglacial_time


Abstract

Thirty-eight new cosmogenic ( 10 Be) exposure ages from the Scoresby Sund region of east Greenland indicate that prominent moraine sets deposited by mountain glaciers date from 780 to 310 yr, approx- imately during the Little Ice Age, from 11660 to 10 630 yr, at the end of the Younger Dryas cold interval or during Preboreal time, and from 13010 to 11630 yr, during lateglacial time. Equilibrium line altitudes (ELAs) interpreted from lateglacial to Early Holocene moraines indicate summertime cooling between 3.9 and 6.6 deg C relative to today’s value, much less than the extreme Younger Dryas cooling registered by Greenland ice cores (mean-annual temperatures of w15 deg C colder than today’s value). This apparent discrepancy between paleotemperature records supports the contention that Younger Dryas cooling was primarily a wintertime phenomenon. 10 Be ages of lateglacial and Holocene moraines show that mountain glaciers during the Little Ice Age were more extensive than at any other time since the Early Holocene Epoch. In addition, 10 Be ages of lateglacial moraines show extensive reworking of boulders with cosmogenic nuclides inherited from prior periods of exposure, consistent with our geomorphic obser- vations and cosmogenic-exposure dating studies in other Arctic regions.

The moraine ridges on the flanks of the Gurreholm Valley, to the south of the Little Ice Age features, suggest three late glacial stages: one at around 12,000 BP, another around 11,500 BP, and a final one around 11,000 BP.  The last one might be referred to as Early Holocene, from the Preboreal phase -- but it might be more appropriate to think in terms of the Older Dryas and Younger Dryas cold episodes, given the spread of dates presented by the authors.  There are also some anomalous dates  from the oldest moraine ridges, suggesting "inherited ages" and some recycling of materials.

So how do these ridges relate to those of Schuchertdal and Kjove Land.?  It would be logical to relate the higher ridges on the south side of Pythagoras Bjerg to the two older phases in Gurreholmsdal -- when rsl might have been at or above 134 m -- implying in turn that the most recent moraine ridges were formed at the time of the 101m stillstand.

Our colleagues Jimmy Cruickshank and Eric Colhoun noticed in 1962 that the pingos in the middle section of the Schuchert Valley were formed on a substrate of shelly silt and clay beds of marine origin, and that these deposits extended at least as far inland as the Little Ice Age moraine of the Roslin Glacier.  The 100m contour crosses the Schuchert sandur between the Roslin Glacier moraine and the Storgletscher moraine, and  Jimmy and Eric suspected that marine beds run up-valley at least as far as that contour -- again suggesting an association between a 101m stillstand and a significant glacier snout position / retreat stage / advance limit.  The associated moraines are yet to be described.

No doubt further work in the area will confirm the full sequence of events.........

The Milne Land Stage, East Greenland

This is a fabulous image of the prominent moraine that runs along the southern edge of the Pythagoras Bjerg plateau, overlooking Hall Bredning and Syd Kap.  The ridge -- in reality a complex of morainic hummocks -- runs approx W-E.  It is assumed by Kelly and Long (2009) to be the lateral moraine of the Nordvestfjord Glacier which was spreading eastwards across the Syd Kap embayment, having crossed the fjord threshold into the wider reaches of Hall Bredning.   They date the morainic complex to the Milne Land Stage as defined by Funder -- and now reasonably well dated to the Younger Dryas or European "Zone III" climatic episode, around 12,000 years ago.

See these posts:

https://brian-mountainman.blogspot.com/2021/09/on-diffluence-holger-danskes-briller.html 

https://brian-mountainman.blogspot.com/2024/01/scoresby-sund-mystery-of-moraine-corner.html

NOTES ON THE GLACIAL GEOLOGY OF EASTERN MILNE LAND, SCORESBY SUND, EAST GREENLAND
Svend Funder

Quote:
Sugden & John (1965) have reported from Kjove Land (fig. l) evidence of two glacier advances during which Nordvestfjord and Schuchert Flod valley contained major ice streams, the oldest being earlier than a shoreline at 134 m, the younger contemporaneous with one at 101 m altitude. It seems 1ikely that these two advances are equivalent to the oldest and one of the younger advances of the Milne Land Stages. It is also interesting to note that Lasca (1969), from Skeldal in Kong Oscars Fjord (150 km NNE of Bregnepynt), reported two major glacier advances during which Kong Oscars Fjord was occupied by ice streams; the younger of these occurred just before the formation of a marine delta at 110 m above present sea-level.

Funder S. 1970. Notes on the glacial geology of eastern Milne Land. Rapport Grønlands Geologiske Undersøgelse 30, 37-42

https://geusjournals.org/index.php/rapggu/article/view/7243/13113

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL067108

In one of my posts I drew attention to the signs of ice flow across the plateau, involving an "overflow" ice stream from the Holger Danskes Briller trough:

I am still convinced that this situation prevailed at some stage during the Last Glaciation (Devensian / Wisconsin / Weichselian), but I now think that the morainic ridges on the plateau are unrelated to that phase, and are related instead to the two "Late Glacial" phases of glaciation which we identified in our 1962 fieldwork:

From Sugden and John (1965) -- based on our 1962 research findings

We were not able to do accurate levelling work up on the plateau, but we were quite convinced that there were traces of the highest regional shoreline -- at 134 m -- beneath some of the higher morainic ridges, and that the ice edge prior to deglaciation was at more than 200m asl.  The bg morainic ridges associated with Hjornemoraene seem to be associated with the 101m sea-level or stillstand -- and tht is esactly the same relationship as that observed at the south-eastern end of the HDB trough, where there is a massive terminal moraine with a planed top at 101m asl.

The ice edge here was probably grounded, and the glacial advance episode came to an end when the ice edge floated off,  permitting the creation of some indistinct shoreline traces at c 134m asl.  The ice front probably retreated back into the Nordvestfjord trough.  After a period of isostatic uplift associated with deglaciation, there was another short-lived advance of the Nordvestfjord Glacier and a marine stillstand at 101m asl.  The ice advanced  at least as far as Nordostbugt, and through the HDB trough as far as the end of the eastern lake, where a massive terminal morainic ridge was created.  Other shoreline traces at the same level were created on the southern flank of the moraine, overlooking Syd Kap Bay.

All things considered, it appears most likely that there were the following Last Glaciation episodes in Kjove Land and on Pythagoras Bjerg:

1.  Large-scale inundation of the landscape by ice from the Nordvestfjord Glacier and from other glaciers in the southern Staunings Alps. Diffluent ice flow through HDB trough and over part of the Pythagoras Bjerg plateau. Large scale isostatic depression of crust.   Relative sea-level maybe 150m asl.

2.  Substantial ice melting and ice edge retreat, leaving Kjove Land ice free and submerged -- highest shorelines indistinct. Marine limit unknown.

3.  Glacier advance, covering Kjove land, Syd Kap Bay etc but leaving Pythagoras Bjerg unglaciated or more probably supporting a local and relatively thin ice cap.  Higher morainic ridges formed on ice edges on the eastern and southern flanks of the Pythagoras Bjerg upland.  Multiple ridges formed between 300m and 100m asl as ice surface dropped.  Shoreline traces at around 134m asl after deglaciation - floating off of ice edge.  Older Dryas age?

4. Renewed glaciation and advance.  Ice from Nordvestfjord flowed eastwards as far as Nordostbugt, leaving a prominent morainic ridge and associated features.  Eastern flank of upland overlooking Kjoveland unaffected by glacier ice.  HDB terminal moraine created.  Sea level at c 101m.

The massive flat-topped HDB terminal Moraine, related to a substantial glacier readvance (Younger Dryas?) through the trough and towards the camera.

Surveying on the flat surface of the HDB terminal moraine -- at 101m asl

5. Glacier retreat up Nordvestfjord and ice edge retreat up all Staunings Alps glacial troughs. Substantial meltwater activity and delta formation at stillstands as sea level dropped episodically due to isostatic recovery and short-lived climatic oscillations. Creation of Gurreholm "staircase" and many other shoreline traces in Schuchertdal.

6. No further substantial glacier advances until Neoglacial / Little Ice Age expansion of valley glaciers within last 500 years.

=====================

I still have some questions regarding the extent of glacier ice in Schuchertdal during the Milne Land stage.  Funder and others think that there was an ice front in the middle section of the valley, south of the Bjørnbo Glacier trough.  I don't think the evidence for that has been presented in adequate detail, although there are references to lateral moraine ridges on the valley sides with a relief of c 5m.  But marine sediments extend up the valley as far as the Roslin Gletscher morainic loop, and they contain shell fragments and other organic materials dating back as far as  11,000 yrs BP.  The details are still to be worked out......... 

Borgbjerg and Löberen glaciers, East Greenland -- the most recent surge

 

There is much in the literature about the surging behaviour of Löberen, on the north shore of Nordvestfjord. We can see it here on the right, in the satellite image.  Since the 1955-65 surge came to an end, the glacier has retreated c 8 km up-valley, leaving relatively few traces on the valley floor.

But I realised when looking at the image that the next glacier to the west -- Borgbjerg Gletscher -- experienced a much bigger surge, probably at the same time, with a calving ice front out in the fjord. Also -- and this is extremely rare -- there is an extensive area of dead ice or ice-cored moraine very close to the shoreline, around 6 km from the present glacier edge. You can see the pockmark pattern of small meltwater pools. As with Löberen next door, the ice edge retreat post-surge is approx 8 km over approx 60 years.

If you look at the glaciers as they are today, they are covered with bright blue meltwater pools -- a characteristic of glaciers that are "healing" themselves following the drastic changes in ice surface elevation caused by a period of rapid ice flow.

Dead Ice Terrain -- Little Ice Age morainic loops

Click to enlarge.......

Sometimes, when you are looking for things on satellite imagery, you get lucky.  If you see an interesting feature and zoom in on it, you sometimes find that the  image manipulation programme used by Google, or Bing, or Apple, flips from one piece of satellite imagery to another.  In the above case, as I zoomed in on some areas of dead ice terrain around the snouts of glaciers on the west shore of Alpefjord in East Greenland, the imagery changed from summer to winter.....

And the result is the above, with (purely by chance) a combination of low winter sun and a sprinkling of snow, showing up the details of dead ice terrain around the snouts of the glaciers decanting down into the trough.  These must be the morainic loops formed in the Little Ice Age, between 1550 and 1950.  There were several ice advances or surges during this period, and as far as I know the precise ages of these features have not yet been fixed.

Little Ice Age Glacier Surges in Schuchertdal, East Greenland

 

Morainic loops and trimlines at the outlets of four glacier catchments in the upper part of Schuchertdal, as defined on modern satellite imagery. The lost spectacular loop is related to the LIA (Little Ice Age) surge of the Roslin Gletscher, which culminated in an ice edge on the eastern edge of Schuchertdal.

Surging behaviour is now recognized on many of the small glaciers (ie less than 40 km long) in the uplands of East Greenland. Those of the Werner Mountains and the Staunings Alps are better documented than those of more remote areas, and Roslin Gletscher and Björnbogletscher are mentioned in a number of research publications such as this one:

https://www.researchgate.net/publication/312395822_The_most_extensive_Holocene_advance_in_the_Stauning_Alper_East_Greenland_occurred_in_the_Little_Ice_Age/figures?lo=1

See also:
https://pubs.usgs.gov/pp/p1386c/p1386c.pdf

See also:
https://brian-mountainman.blogspot.com/2010/09/ivar-bardarsons-glacier-then-and-now.html

The last surge (or advance) of the Björnbo Gletscher was contained within its upland trough, but that of the Roslin Gletscher (once called Ivaar Bardarssons Gletscher) involved the creation of a spectacular morainic loop which effectively blocked the Schuchert Valley -- and this has attracted attention since the early days of map making and mineral exploration in the 1950's.

Roslin Gletscher ice front in 1954 -- photo by Ernst Hofer. He described the ice front as being 30m high at the time.

The maximum extent of the Little Ice Age surge morainic loop. The 1954 ice edge is also demarcated. This is possible because some of the landforms -- such as the large lake -- can be identified on all existing aerial photos.

I am quite intrigued by the Ernst Hofer oblique photograph, because it shows a steep ice front and an extremely rough and crevassed ice surface. This suggests to me that the photo was taken shortly after the culmination of a new surge that might have occurred around 1950. When we walked across this glacier in 1962 the ice edge was more or less in the same place, but the glacier surface presented us with no difficulties at all, and we did not even need to rope up. So I think we might have signs here of two (or maybe several) surges, of more or less equal extent.

Were these surges matched in time by the surges in the adjacent glaciers?

At the top of the photo we can see the maximum extent of the ice lobe at the head of the Schuchert Valley -- carrying ice from several linked glaciers -- namely Schuchert Gletscher itself, Arcturus Gletscher, Sirius Gletscher, Aldebaran Gletscher and a number of smaller tributary glaciers in the Werner Mountains. The ice edge has since retreated by about 4 km. 

The Storgletscher advance, also involving ice from Gannochy Gletscher, also pushed across to the eastern edge of the Schuchert Valley -- but there was also an input from a smaller unnamed glacier to the south. The extent of the ice-cored moraine (with abundant small meltwater lakes) is very clear on the satellite image.

The timing and nature of these surges will no doubt be the subjects of future investigations. But how do they relate to the surging glaciers of NW Iceland? In the area which Dave Sugden and I studied in 1960, and which I revisited with the Vestfirdir Project in 1973-76, the surging behaviour of the Drangajokull outlet glaciers (particularly Kaldalonsjokull, Reykjarfjardarsjokull and Leirufjardarsjokull) is now well documented, with the most marked advances of the ice edges dated to c 1740, 1850 and 1994.  In NW Iceland there does not seem to have been a big readvance or surge around 1950.

https://brian-mountainman.blogspot.com/2022/10/the-end-of-kaldalonsjokull.html

https://brian-mountainman.blogspot.com/2019/02/drangajokull-and-kaldalon-nw-iceland.html

As for the other glaciers in NE Greenland, we do know that some of the Nordvestfjord glaciers including Oxford Gletscher and Løberen are liable to surging behaviour, and that the latter (the "galloping glacier" started a massive surge in 1950 and which continued until about 1965.

https://brian-mountainman.blogspot.com/2021/10/oxford-gletscher-surface-thermal-regime.html

https://brian-mountainman.blogspot.com/2013/08/and-now-for-galloping-glacier.html

https://brian-mountainman.blogspot.com/2024/02/lberen-greenlands-galloping-glacier.html

So I have a little theory that there might have been a regional "surge event" in the Staunings Alps area in the period 1950-1960 which affected many of the smaller glaciers which originated in the uplands, and that this event was just slightly less dramatic and less extensive than some of the other surges associated with the Little Ice Age in Greenland and Iceland.


===================


To set this in context:

Glacier response to the Little Ice Age during the Neoglacial cooling in Greenland
Kurt H. Kjær et al, 2022.
Earth-Science Reviews
Volume 227, April 2022, 103984

https://www.sciencedirect.com/science/article/pii/S001282522200068X

Abstract

In the Northern Hemisphere, an insolation driven Early to Middle Holocene Thermal Maximum was followed by a Neoglacial cooling that culminated during the Little Ice Age(LIA). Here, we review the glacier response to this Neoglacial cooling in Greenland. Changes in the ice margins of outlet glaciers from the Greenland Ice Sheet as well as local glaciers and ice caps are synthesized Greenland-wide. In addition, we compare temperature reconstructions from ice cores, elevation changes of the ice sheet across Greenland and oceanographic reconstructions from marine sediment cores over the past 5,000 years. The data are derived from a comprehensive review of the literature supplemented with unpublished reports. Our review provides a synthesis of the sensitivity of the Greenland ice margins and their variability, which is critical to understanding how Neoglacial glacier activity was interrupted by the current anthropogenic warming. We have reconstructed three distinct periods of glacier expansion from our compilation: two older Neoglacial advances at 2,500 – 1,700 yrs. BP (Before Present = 1950 CE, Common Era) and 1,250 – 950 yrs. BP; followed by a general advance during the younger Neoglacial between 700-50 yrs. BP, which represents the LIA. There is still insufficient data to outline the detailed spatio-temporal relationships between these periods of glacier expansion. Many glaciers advanced early in the Neoglacial and persisted in close proximity to their present-day position until the end of the LIA. Thus, the LIA response to Northern Hemisphere cooling must be seen within the wider context of the entire Neoglacial period of the past 5,000 years. Ice expansion appears to be closely linked to changes in ice sheet elevation, accumulation, and temperature as well as surface-water cooling in the surrounding oceans. At least for the two youngest Neoglacial advances, volcanic forcing triggering a sea-ice /ocean feedback, could explain their initiation. There are probably several LIA glacier fluctuations since the first culmination close to 1250 CE (Common Era) and available data suggests ice culminations in the 1400s, early to mid-1700s and early to mid-1800s CE. The last LIA maxima lasted until the present deglaciation commenced around 50 yrs. BP (1900 CE). The constraints provided here on the timing and magnitude of LIA glacier fluctuations delivers a more realistic background validation for modelling future ice sheet stability.

and this:

https://www.sciencedirect.com/science/article/abs/pii/S0277379108001765

Meredith A. Kelly et al, 2008
A 10Be chronology of lateglacial and Holocene mountain glaciation in the Scoresby Sund region, east Greenland: implications for seasonality during lateglacial time.
Quaternary Science Reviews
Volume 27, Issues 25–26, December 2008, Pages 2273-2282

Abstract

Thirty-eight new cosmogenic (10Be) exposure ages from the Scoresby Sund region of east Greenland indicate that prominent moraine sets deposited by mountain glaciers date from 780 to 310 yr, approximately during the Little Ice Age, from 11 660 to 10 630 yr, at the end of the Younger Dryas cold interval or during Preboreal time, and from 13 010 to 11 630 yr, during lateglacial time. Equilibrium line altitudes (ELAs) interpreted from lateglacial to Early Holocene moraines indicate summertime cooling between ∼3.9 and 6.6 °C relative to today's value, much less than the extreme Younger Dryas cooling registered by Greenland ice cores (mean-annual temperatures of ∼15 °C colder than today's value). This apparent discrepancy between paleotemperature records supports the contention that Younger Dryas cooling was primarily a wintertime phenomenon. 10Be ages of lateglacial and Holocene moraines show that mountain glaciers during the Little Ice Age were more extensive than at any other time since the Early Holocene Epoch. In addition, 10Be ages of lateglacial moraines show extensive reworking of boulders with cosmogenic nuclides inherited from prior periods of exposure, consistent with our geomorphic observations and cosmogenic-exposure dating studies in other Arctic regions.


.......... and this:


https://www.researchgate.net/publication/312395822_The_most_extensive_Holocene_advance_in_the_Stauning_Alper_East_Greenland_occurred_in_the_Little_Ice_Age


The most extensive Holocene advance in the Stauning Alper, East Greenland, occurred in the Little Ice Age

Brenda L. Hall, Carlo Baroni & George H. Denton
Polar Research 27(2)

DOI:   10.3402/polar.v27i2.6171


Abstract

We present glacial geologic and chronologic data concerning the Holocene ice extent in the Stauning Alper of East Greenland. The retreat of ice from the late-glacial position back into the mountains was accomplished by at least11 000 cal years B.P. The only recorded advance after this time occurred duringthe past few centuries (the Little Ice Age). Therefore, we postulate that the Little Ice Age event represents the maximum Holocene ice extent in this part of East Greenland.

================

The paper by Hall, Baroni and Denton confirms what David Sugden and myself proposed in 1965: namely that by around 11,000 yrs BP most glacier ice has melted away in Schuchertdal, allowing a substantial marine incursion of the valley -- at least as far up-valley as the side trough of the Roslin Gletscher. This allowed the creation of marine terraces at and below 67 m asl. This may have coincided with the formation of the major marine delta terrace at c 67m in the "Gurreholm Staircase" as measured by David and me in 1962.  Radiocarbon dating of marine mollusca contained within these terrace remnants suggests ice-free conditions at around 10,700 yrs BP. The presence of marine terrace fragments all the way down the valley confirms that there was no substantial Neoglacial ice advance until the Little Ice Age  -- at which time the spectacular loops of moraine at the glacier fronts were created.

https://www.researchgate.net/publication/262414669_The_Raised_Marine_Features_of_Kjove_Land_East_Greenland

https://polarresearch.net/index.php/polar/article/view/3201/pdf

Funder S. 1970. Notes on the glacial geology of eastern Milne Land. Rapport Grønlands Geologiske Undersøgelse 30, 37-42

https://geusjournals.org/index.php/rapggu/article/view/7243/13113

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL067108

Funder S. 1970. Notes on the glacial geology of eastern Milne

Land.

Rapport Grønlands Geologiske Undersøgelse 30

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42

Funder S. 1970. Notes on the glacial geology of eastern Milne

Land.

Rapport Grønlands Geologiske Undersøgelse 30

,37



42

Funder S. 1970. Notes on the glacial geology of eastern Milne

Land.

Rapport Grønlands Geologiske Undersøgelse 30

,37



42

A Stonehenge prophecy

 

Thanks to Tony for noticing this one. It was on one of the Wiltshire Facebook pages -- an advert dating from (I guess) around 1950. Quite apart from the pun about a wilting Stonehenge, the advert is strangely prophetic.....

Good adverts home in on things that others do not see -- and in this case the advertising agency working for Shell has recognized the desire of many people (not all!) to worship at the Stonehenge shrine............ Some might see this as blasphemy, but the idea that Stonehenge is a religious iconic structure worthy of respect and even reverence is central to the EH marketing of today!

So the idea that Stonehenge is -- or should be -- a place of worship is humorous at one level but concerning at another. After all, nobody is worshipping a set of beliefs or a holy book or a place of profound thoughts or ideas here, unless maybe we go with the Druids who have commandeered Stonehenge as a key symbolic site and who have attached to it their own theology. This is what Google tells us: For druids, modern-day spiritualists linked to the ancient Celtic religious order, Stonehenge has a centuries-long importance, and they will be there to perform dawn rituals around the solstice in their traditional white robes. It's effectively all about the cycle of life, of death and rebirth.  Of course, it is also about sunrise, and the summer solstice, and about respect for nature, peace and love.........

https://solstice-tours.com/stonehenge-druid-pagan-solstice-celebration.htm#:~:text=These%20seasonal%20festivals%20can%20be,a%20small%20group%20of%20Druids

So the midsummer and widwinter solstices are celebrated by druids, hippies (oops -- do they still exist?) and tourists in their own peculiar fashion, with a minimum of control by EH. The ceremonies at Midsummer and Midwinter are unashamedly pagan and are of course perfectly harmless -- and those who participate in them are uplifted by the cameraderie and the high spirits, with the assistance of drums, bugles and assorted interesting substances. Other religions are allowed, but keep a low profile.... and we cannot doubt that the events are, for many people, profoundly spiritual and meaningful.

But the Stonehenge religious experience is of course "manufactured" just as the Welsh National Eisteddfod was invented and manufactured by Iolo Morgannwg, who convinced himself, and the world, that he was rediscovering something ancient which had been more or less forgotten. So now the religious life of Stonehenge is a very strange mish-mash of religious beliefs, ceremonial, pseudo-history,  mysticism, spirituality, song and dance, fancy dress and a good deal else.  But be in no doubt -- at the centre of it all is the Great God Mammon.  And as the old Shell advert reminded us long ago, there's money in those old stones.

The Ice Age pioneers

Charles Lyell

Louis Agassiz

Andrew Ramsay

Archibald Geikie

James Croll

James Geikie

Carvill Lewis

Thomas Jehu

John Wesley Judd

Henry Hicks

Putting faces to the names.  The standout scientists were Croll, Jehu and Judd, who were decades ahead of their time.

Some of the above were fieldworkers and others were more concerned about theory. Some knew Pembrokeshire, and some did not. But what they have in common is that they were comprehensively ignored by Herbert Thomas when he wrote his famous bluestone paper in 1923 and pronounced that "The geological evidence proves conclusively that although Pembrokeshire was crossed in a south-easterly direction by a lobe of the Irish Sea ice-sheet the front of this ice-sheet never reached across or far up the Bristol Channel."  This of course is a lie -- he knew full well that the geological evidence shows that the ice that crossed Pembrokeshire extended eastwards at least as far as Glamorgan and across to the other side of the Bristol Channel.