Friday, 5 August 2011
The Awkward Heelstone
David Field and Trevor Pearson say: "It was a good point made by Johnson (2008, 121) that the Heel Stone is too awkward and bulky a shape to move on rollers and it, at least, is unlikely to have travelled far."
It may be a bit rounder but is no bulkier or more awkward than the other stones - and it has a nice flat side to lay on a cradle. Their support for Johnson's inexplicable comment is surprising.
Field & Pearson on The Sarsens
STONEHENGE WORLD HERITAGE SITE LANDSCAPE PROJECT
STONEHENGE, AMESBURY, WILTSHIRE
ARCHAEOLOGICAL SURVEY REPORT
David Field and Trevor Pearson
Research Department Report Series
NGR: SU 12244219
© English Heritage
109-2010
ISSN 1749-8775
Sarsen boulders occur naturally within the area as remnants of a crust of siliceous sandstone formed in the Eocene (55-38 m years) that once overlay the chalk but which has long since broken up, eroded, weathered and many drifted into valleys (Green 1997, 260). Like fint, where present they might retard local weathering of the chalk. Compared to the Marlborough Downs, however, remnants are fewer on Salisbury Plain and what little remained following periglacial processes appears for the most part to have been long cleared.
The source of the stones:
Inigo Jones was the frst to point out that the stones incorporated in the monument need not have come from Ireland but that building stone was available locally, for example at Chilmark. Even so he was inclined to believe that the sarsen derived from quarries on the Marlborough Downs where sarsen boulders were plentiful. More recently, while recognising the lack of large sarsen available on the Marlborough Downs, Green (1997) assumed that the Stonehenge examples must nevertheless have come from that area as it is the place of the greatest accumulation and choice. Heavy mineral analysis on samples from Stonehenge and the Marlborough Downs (Howard 1982), however, indicated that there was a considerable degree of variation between them.
Essentially, sarsen is present in greater or lesser numbers right across central southern England (Bowen and Smith 1977). Within Wiltshire and south of the Marlborough Downs it is widely present in the Vale of Pewsey and there remains a veneer on Salisbury Plain, though early agriculture in both of these areas may have contributed to the thin distribution. A boulder neatly broken into at least three pieces occurred in Late Bronze Age-Early Iron Age contexts in the East Chisenbury midden (McOmish et al 2010, 82) and this may have been the fate of a great many that proved an obstacle to the widespread establishment of ‘Celtic’ felds on Salisbury Plain to the north of Stonehenge.
William Long (1876, 142) quoted John Aubrey regarding the King Barrows. ‘At the end of these graves were stones, which the people of late years, sc. Since 1640, have fetcht away…’ and Stukeley appears to have repeated this (Burl & Mortimer 2005, 29). In addition he noted that there was a large stone in Durrington Field, one in the river at Milford and another in the feld to the west of Figheldean c3 miles from Stonehenge. (Stukeley 1740, 37: Burl & Mortimer 2005, 31).
William Cunnington (Cunnington Mss Devizes Book 9) described how, in the early years of the 19th century, farmers ploughed up sarsen in the vicinity of Stonehenge and there is suffcient evidence remaining to indicate that he was not mistaken. Cunnington wrote that sarsen is found ‘upon the Downs, a foot or two under the ground their supefces are rounded by attrition’ while ‘others ploughed up near Stonehenge appear to have been bored through by the Toredo’ (Cunnington MSS Book 9 Devizes Museum). Sarsen was used at Boles Barrow, Arn Hill and elsewhere on Salisbury
Plain in long barrow construction, while six large extant boulders lie to the north of Stonehenge at Robin Hoods Ball and three more in the ditch of the Figheldean 31 long barrow (McOmish et al 2002, 151-2). Others were noted on early Ordnance Survey maps.
Hoare wavered and considered on one hand that the Marlborough Downs was a potential source but also that the origin of the sarsens at Stonehenge could be local, ‘the plains adjoining Stonehenge might very probably have furnished stones suffciently large’ (Hoare 1812, 149, 152). The Rev E Duke (1846, 170) questioned the assumption that the sarsens had been brought from the Marlborough Downs and noted that none are now to be found of that size there. Instead, he suggested that the boulders were ‘quarried from a continuous stratum’ and indeed such seams are thought to exist around Avebury (Barker 1985, 21). Petrie noted that there were few or no sarsens of the required size to be found elsewhere, that is on the Marlborough Downs, and
considered whether the very position of Stonehenge was determined by the presence of a quantity of sarsens that had derived from denuded beds formerly lying over the chalk and on balance thought that they had been collected from the immediate vicinity.
Gowland similarly considered them brought from ‘within a radius of not many miles’ and ‘probably at no great distance from the spot where the structure stands’ (Gowland 1902, 75, 115) rather than from a distant locality, while the geologist Prof J W Judd (1901, 115-6) thought likewise and that they had moved ‘only a few hundred yards’. H H Thomas (1923, 242) considered that they may have come from ‘the site of Stonehenge itself ’. It was a good point made by Johnson (2008, 121) that the Heel Stone is too awkward and bulky a shape to move on rollers and it, at least, is unlikely to have travelled far. Equally the much smaller undressed Station Stones may be quite local. It is after all possible to fnd larger stones on Salisbury Plain without having to travel to the Marlborough Downs for them. If these points are accepted it becomes easier to
acknowledge that the sarsen group as a whole may not have been the product of a heroic journey.
The diffculty in working sarsen is well-known (Fig 14) and while weathered sarsen lying on the surface has an exceedingly tough crust, Isobel Geddes crucially pointed out that in contrast
buried sarsen is soft and can be easily worked (Geddes 2000: also Bowen & Smith 1977, 189). This was something also noted by Cunnington: ‘when frst dug out of the ground they are soft like freestone just quarried….if broken you may crumble the inside pieces between your fngers like Lump Sugar’ (Cunnington MSS Book 4, 34). Geddes also pointed out that the only place where sarsen boulders large enough for Stonehenge monoliths have been found in recent times is below the surface in swallow holes where they have been protected from weathering (Bowen & Smith 1977, 189 refer to this also). It is worth noting that there are at least two such holes, potentially more, in the Stonehenge landscape.
STONEHENGE, AMESBURY, WILTSHIRE
ARCHAEOLOGICAL SURVEY REPORT
David Field and Trevor Pearson
Research Department Report Series
NGR: SU 12244219
© English Heritage
109-2010
ISSN 1749-8775
Sarsen boulders occur naturally within the area as remnants of a crust of siliceous sandstone formed in the Eocene (55-38 m years) that once overlay the chalk but which has long since broken up, eroded, weathered and many drifted into valleys (Green 1997, 260). Like fint, where present they might retard local weathering of the chalk. Compared to the Marlborough Downs, however, remnants are fewer on Salisbury Plain and what little remained following periglacial processes appears for the most part to have been long cleared.
The source of the stones:
Inigo Jones was the frst to point out that the stones incorporated in the monument need not have come from Ireland but that building stone was available locally, for example at Chilmark. Even so he was inclined to believe that the sarsen derived from quarries on the Marlborough Downs where sarsen boulders were plentiful. More recently, while recognising the lack of large sarsen available on the Marlborough Downs, Green (1997) assumed that the Stonehenge examples must nevertheless have come from that area as it is the place of the greatest accumulation and choice. Heavy mineral analysis on samples from Stonehenge and the Marlborough Downs (Howard 1982), however, indicated that there was a considerable degree of variation between them.
Essentially, sarsen is present in greater or lesser numbers right across central southern England (Bowen and Smith 1977). Within Wiltshire and south of the Marlborough Downs it is widely present in the Vale of Pewsey and there remains a veneer on Salisbury Plain, though early agriculture in both of these areas may have contributed to the thin distribution. A boulder neatly broken into at least three pieces occurred in Late Bronze Age-Early Iron Age contexts in the East Chisenbury midden (McOmish et al 2010, 82) and this may have been the fate of a great many that proved an obstacle to the widespread establishment of ‘Celtic’ felds on Salisbury Plain to the north of Stonehenge.
William Long (1876, 142) quoted John Aubrey regarding the King Barrows. ‘At the end of these graves were stones, which the people of late years, sc. Since 1640, have fetcht away…’ and Stukeley appears to have repeated this (Burl & Mortimer 2005, 29). In addition he noted that there was a large stone in Durrington Field, one in the river at Milford and another in the feld to the west of Figheldean c3 miles from Stonehenge. (Stukeley 1740, 37: Burl & Mortimer 2005, 31).
William Cunnington (Cunnington Mss Devizes Book 9) described how, in the early years of the 19th century, farmers ploughed up sarsen in the vicinity of Stonehenge and there is suffcient evidence remaining to indicate that he was not mistaken. Cunnington wrote that sarsen is found ‘upon the Downs, a foot or two under the ground their supefces are rounded by attrition’ while ‘others ploughed up near Stonehenge appear to have been bored through by the Toredo’ (Cunnington MSS Book 9 Devizes Museum). Sarsen was used at Boles Barrow, Arn Hill and elsewhere on Salisbury
Plain in long barrow construction, while six large extant boulders lie to the north of Stonehenge at Robin Hoods Ball and three more in the ditch of the Figheldean 31 long barrow (McOmish et al 2002, 151-2). Others were noted on early Ordnance Survey maps.
Hoare wavered and considered on one hand that the Marlborough Downs was a potential source but also that the origin of the sarsens at Stonehenge could be local, ‘the plains adjoining Stonehenge might very probably have furnished stones suffciently large’ (Hoare 1812, 149, 152). The Rev E Duke (1846, 170) questioned the assumption that the sarsens had been brought from the Marlborough Downs and noted that none are now to be found of that size there. Instead, he suggested that the boulders were ‘quarried from a continuous stratum’ and indeed such seams are thought to exist around Avebury (Barker 1985, 21). Petrie noted that there were few or no sarsens of the required size to be found elsewhere, that is on the Marlborough Downs, and
considered whether the very position of Stonehenge was determined by the presence of a quantity of sarsens that had derived from denuded beds formerly lying over the chalk and on balance thought that they had been collected from the immediate vicinity.
Gowland similarly considered them brought from ‘within a radius of not many miles’ and ‘probably at no great distance from the spot where the structure stands’ (Gowland 1902, 75, 115) rather than from a distant locality, while the geologist Prof J W Judd (1901, 115-6) thought likewise and that they had moved ‘only a few hundred yards’. H H Thomas (1923, 242) considered that they may have come from ‘the site of Stonehenge itself ’. It was a good point made by Johnson (2008, 121) that the Heel Stone is too awkward and bulky a shape to move on rollers and it, at least, is unlikely to have travelled far. Equally the much smaller undressed Station Stones may be quite local. It is after all possible to fnd larger stones on Salisbury Plain without having to travel to the Marlborough Downs for them. If these points are accepted it becomes easier to
acknowledge that the sarsen group as a whole may not have been the product of a heroic journey.
The diffculty in working sarsen is well-known (Fig 14) and while weathered sarsen lying on the surface has an exceedingly tough crust, Isobel Geddes crucially pointed out that in contrast
buried sarsen is soft and can be easily worked (Geddes 2000: also Bowen & Smith 1977, 189). This was something also noted by Cunnington: ‘when frst dug out of the ground they are soft like freestone just quarried….if broken you may crumble the inside pieces between your fngers like Lump Sugar’ (Cunnington MSS Book 4, 34). Geddes also pointed out that the only place where sarsen boulders large enough for Stonehenge monoliths have been found in recent times is below the surface in swallow holes where they have been protected from weathering (Bowen & Smith 1977, 189 refer to this also). It is worth noting that there are at least two such holes, potentially more, in the Stonehenge landscape.
Thursday, 4 August 2011
Stonehenge Building Climate
Historical weather events.
3000 BC onwards: Bronze Age recovery (after previous, relatively short-lived downturn): freedom from major storms, excessive rainfall etc., and renewed increase in temperature. Glaciers & 'permanent' snow-patches less prominent. Increase in forest cover back to more 'exposed' (in modern terms) western / upland areas. Renewed building of stone circles - possibly as observatories - this suggests lower cloud cover amounts than before. The Elm & Lime tree 'northern-most' line moved north, and woods probably grew on Orkney & exposed NW Scotland, therefore again implying milder and, perhaps more importantly, much less windy conditions than the modern era.
Ref: Climate, history and the modern world. H.H. Lamb Methuen 1982
Ref: The English climate. H.H. Lamb English Universities Press 1964
3000 BC onwards: Bronze Age recovery (after previous, relatively short-lived downturn): freedom from major storms, excessive rainfall etc., and renewed increase in temperature. Glaciers & 'permanent' snow-patches less prominent. Increase in forest cover back to more 'exposed' (in modern terms) western / upland areas. Renewed building of stone circles - possibly as observatories - this suggests lower cloud cover amounts than before. The Elm & Lime tree 'northern-most' line moved north, and woods probably grew on Orkney & exposed NW Scotland, therefore again implying milder and, perhaps more importantly, much less windy conditions than the modern era.
Ref: Climate, history and the modern world. H.H. Lamb Methuen 1982
Ref: The English climate. H.H. Lamb English Universities Press 1964
Moving Sarsen Stones on Ice
Bearing Capacity of Freshwater Ice
Gold Formula
The most accepted ice capacity guideline, developed by Dr. Lorne Gold of the National Research Council of Canada. Dr. Gold dedicated most of his professional career to ice related engineering studies.
Ice Capacity Using the Gold Formula
P= allowable load capacity of the ice in kilograms.
H= Blue or natural ice thickness in centimeters
W= White ice (flood ice) thickness in centimeters
For solid blue ice:
P= 7.03 X H2
For blue and white ice combined:
P= 7.03 X (H + 1/2W)2
METRIC
Depth
(Cms) Capacity (Kgs)
2 = 28
4 = 112
6 = 253
8 = 450
10 = 703
12 = 1,012
14 = 1,378
16 = 1,780
18 = 2,278
20 = 2,812
22 = 3,403
24 = 4,049
26 = 4,752
28 = 5,512
30 = 6,327
32 = 7,199
34 = 8,127
36 = 9,111
38 = 10,151
40 = 11,248
42 = 12,401
44 = 13,610
46 = 14,876
48 = 16,197
50 = 17,575
52 = 19,000
54 = 20,499
56 = 22,046
58 = 23,649
60 = 25,308
62 = 27,023
64 = 28,795
66 = 30,623
68 = 32,507
70 = 34,447
72 = 36,443
74 = 38,496
76 = 40,605
78 = 42,771
80 = 44,992
82 = 47,270
84 = 49,604
86 = 51,994
88 = 54,440
90 = 56,943
92 = 59,502
94 = 62,117
96 = 64,788
98 = 67,516
100 = 70,300
So a 50 tonne sarsen stone would need continuous good ice of 85cm depth. Flooded marsh land and flowing rivers and ice on the edge of a channel are not "good" ice and so a greater depth would be needed.
Upto 75 large stones were moved so these conditions would have to have been met repeatedly for them to have been skidded down the frozen River Avon.
Gold Formula
The most accepted ice capacity guideline, developed by Dr. Lorne Gold of the National Research Council of Canada. Dr. Gold dedicated most of his professional career to ice related engineering studies.
Ice Capacity Using the Gold Formula
P= allowable load capacity of the ice in kilograms.
H= Blue or natural ice thickness in centimeters
W= White ice (flood ice) thickness in centimeters
For solid blue ice:
P= 7.03 X H2
For blue and white ice combined:
P= 7.03 X (H + 1/2W)2
METRIC
Depth
(Cms) Capacity (Kgs)
2 = 28
4 = 112
6 = 253
8 = 450
10 = 703
12 = 1,012
14 = 1,378
16 = 1,780
18 = 2,278
20 = 2,812
22 = 3,403
24 = 4,049
26 = 4,752
28 = 5,512
30 = 6,327
32 = 7,199
34 = 8,127
36 = 9,111
38 = 10,151
40 = 11,248
42 = 12,401
44 = 13,610
46 = 14,876
48 = 16,197
50 = 17,575
52 = 19,000
54 = 20,499
56 = 22,046
58 = 23,649
60 = 25,308
62 = 27,023
64 = 28,795
66 = 30,623
68 = 32,507
70 = 34,447
72 = 36,443
74 = 38,496
76 = 40,605
78 = 42,771
80 = 44,992
82 = 47,270
84 = 49,604
86 = 51,994
88 = 54,440
90 = 56,943
92 = 59,502
94 = 62,117
96 = 64,788
98 = 67,516
100 = 70,300
So a 50 tonne sarsen stone would need continuous good ice of 85cm depth. Flooded marsh land and flowing rivers and ice on the edge of a channel are not "good" ice and so a greater depth would be needed.
Upto 75 large stones were moved so these conditions would have to have been met repeatedly for them to have been skidded down the frozen River Avon.
Wednesday, 3 August 2011
Stonehenge and Avebury seminar at Devizes – a report
Stonehenge and Avebury seminar at Devizes – a report
Mike Parker Pearson ....told us of some recent fieldwork he’d done near the Devil’s Den, a cromlech at the bottom of the long valley running south from Fyfield Down and the Grey Wethers, a valley that must have been a stone chute for the sarsens sliding down the valley sides. MPP said that he and Mike Pitts had spotted large depressions in the valley above the Den, and he suggested that these might have been the resting places of sarsen stones before they made the journey to Stonehenge. So, what would that journey have been? It’s very unlikely that they’d have been dragged up the valley and then down again to Avebury. So the only reasonable suggestion is that they went down Clatford Bottom, the valley continuation to Clatford, and crossed the river Kennet. Crossing the Kennet would require a causeway – and MPP thinks he’s spotted one beside the existing bridge. Exciting, or what? The obvious route then is to take the easy slopes through Lockeridge to Knap Hill, and then down to Marden henge, and the headwaters of the Avon. Perhaps the Marden henge monumentalizes the crossing of the Avon? The Clatford hypothesis should be easy enough to test and, if MPP is right about a heavily-piled Kennet causeway strong enough to carry stones weighing up to 50 tons, there could still be some mud-preserved remains in the river bottom. And that could lead to an RC dating that would date Stonehenge precisely.
Mike Parker Pearson ....told us of some recent fieldwork he’d done near the Devil’s Den, a cromlech at the bottom of the long valley running south from Fyfield Down and the Grey Wethers, a valley that must have been a stone chute for the sarsens sliding down the valley sides. MPP said that he and Mike Pitts had spotted large depressions in the valley above the Den, and he suggested that these might have been the resting places of sarsen stones before they made the journey to Stonehenge. So, what would that journey have been? It’s very unlikely that they’d have been dragged up the valley and then down again to Avebury. So the only reasonable suggestion is that they went down Clatford Bottom, the valley continuation to Clatford, and crossed the river Kennet. Crossing the Kennet would require a causeway – and MPP thinks he’s spotted one beside the existing bridge. Exciting, or what? The obvious route then is to take the easy slopes through Lockeridge to Knap Hill, and then down to Marden henge, and the headwaters of the Avon. Perhaps the Marden henge monumentalizes the crossing of the Avon? The Clatford hypothesis should be easy enough to test and, if MPP is right about a heavily-piled Kennet causeway strong enough to carry stones weighing up to 50 tons, there could still be some mud-preserved remains in the river bottom. And that could lead to an RC dating that would date Stonehenge precisely.
Tuesday, 2 August 2011
Cannings Marsh Map - With Slopes And Sarsen Route Marked
A reduced image of a map (Click for larger) showing the approximate extent of Cannings Marsh and other wet areas. Slopes are marked in brown. The most logical route for transporting the sarsens from the Marlborough Downs to the top of Redhorn Hill is shown. (The only route across Salisbury Plain that is level enough starts at the top of Redhorn Hill). The track up is a manageable slope. It will be noted that the route goes through Marden Henge.
Monday, 1 August 2011
How Did The Sarsen Stones Get To Stonehenge?
This is the standard proposed route for the transport of the sarsen stones to Stonehenge.
This blog is open ongoing research in which I am investigating why this is wrong, or at least extremely unlikely.
Any helpful comments are welcome as the hypotheses of alternative routes are tried.
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