River North Esk - an excursion - Revision history

Scotfot at 09:51, 7 November 2015

2015-11-07T09:51:44Z

← Older revision		Revision as of 10:51, 7 November 2015
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	[[File:Lothian Geology cover.jpg\|thumb\|100px\|right\|[http://www.edinburghgeolsoc.org/p_sales.html#lothiangeology Buy the book]]]		[[File:Lothian Geology cover.jpg\|thumb\|100px\|right\|[http://www.edinburghgeolsoc.org/p_sales.html#lothiangeology Buy the book]]]
	'''By W. Baird. From: Lothian geology an excursion guide. Edited by A.D. McAdam and E.N.K. Clarkson. 1996'''		'''By W. Baird. From: [[Lothian Geology: an excursion guide\|Lothian geology: an excursion guide]]. Edited by A.D. McAdam and E.N.K. Clarkson. 1996'''

	O.S. 1:50000 Sheet 66 Edinburgh		O.S. 1:50000 Sheet 66 Edinburgh

Scotfot at 21:17, 6 March 2015

2015-03-06T21:17:38Z

← Older revision		Revision as of 22:17, 6 March 2015
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	Continue beyond the Penicuik sewage works, across the bridge at Harper's Brae (NT 245 605) and take the walkway upstream on the east bank of the river to a point 60 m upstream from the wooden walkway bridge. Exposed just at water level on the east bank. is a limestone correlated with the Calmy Limestone. Return to the bridge at Harper's Brae and take the Kirkhill Road which rises steeply into Penicuik.		Continue beyond the Penicuik sewage works, across the bridge at Harper's Brae (NT 245 605) and take the walkway upstream on the east bank of the river to a point 60 m upstream from the wooden walkway bridge. Exposed just at water level on the east bank. is a limestone correlated with the Calmy Limestone. Return to the bridge at Harper's Brae and take the Kirkhill Road which rises steeply into Penicuik.

	== At all times follow: [http://www.outdooraccess-scotland.com/the-act-and-the-code/introduction The Scottish Access Code]and [http://www.geologistsassociation.org.uk/downloads/Code%20of%20conduct/Code%20for%20fieldwork%20combined.pdf Code of Conduct for Fieldwork] ==		{{EGwalks}}


	[[category:5. Midland Valley of Scotland]]		[[category:5. Midland Valley of Scotland]]

Scotfot: /* 9. Firth House: Sandstone, Artificial Tufa */

2015-03-03T09:05:11Z

9. Firth House: Sandstone, Artificial Tufa

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	==== 9. Firth House: Sandstone, Artificial Tufa ====		==== 9. Firth House: Sandstone, Artificial Tufa ====

	When the water is low, and one is clad in wellington boots, it is possible to leave the track of the railway at the Firth Viaduct, descend to the riverside and follow the river bank around the two spurs opposite Firth House. About 100 m downstreum from the waterfall formed by a small stream on the south bank between Auchendinny House and Firth House. well-defined current bedding can be seen on the massive bottom post of two major sandstone ribs exposed high on the cliffs of the south bank. Only 25 m upstream from the waterfall, 15 m of the river margin arc covered in a ~~culcareous~~ tufa deposited by water seeping from further up the bank. This tufa, although appearing similar to naturally occurring tufa, has been deposited as a secondary mineral by water percolating through the caustic dump of the Dalmore Paper Mill - an interesting example of a geological feature resulting from man's activities.		When the water is low, and one is clad in wellington boots, it is possible to leave the track of the railway at the Firth Viaduct, descend to the riverside and follow the river bank around the two spurs opposite Firth House. About 100 m downstreum from the waterfall formed by a small stream on the south bank between Auchendinny House and Firth House. well-defined current bedding can be seen on the massive bottom post of two major sandstone ribs exposed high on the cliffs of the south bank. Only 25 m upstream from the waterfall, 15 m of the river margin arc covered in a calcareous tufa deposited by water seeping from further up the bank. This tufa, although appearing similar to naturally occurring tufa, has been deposited as a secondary mineral by water percolating through the caustic dump of the Dalmore Paper Mill - an interesting example of a geological feature resulting from man's activities.

	==== 10 and 11. Dalmore Mill: Roslin Sandstone ====		==== 10 and 11. Dalmore Mill: Roslin Sandstone ====

Scotfot at 19:19, 22 February 2015

2015-02-22T19:19:46Z

← Older revision		Revision as of 20:19, 22 February 2015
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	[[File:Lothian Geology cover.jpg\|thumb\|100px\|right\|[http://www.edinburghgeolsoc.org/p_sales.html#lothiangeology Buy the book]]]		[[File:Lothian Geology cover.jpg\|thumb\|100px\|right\|[http://www.edinburghgeolsoc.org/p_sales.html#lothiangeology Buy the book]]]
	'''By W. Baird. From: Lothian geology ~~and~~ excursion guide. Edited by A.D. McAdam and E.N.K. Clarkson. 1996'''		'''By W. Baird. From: Lothian geology an excursion guide. Edited by A.D. McAdam and E.N.K. Clarkson. 1996'''

	O.S. 1:50000 Sheet 66 Edinburgh		O.S. 1:50000 Sheet 66 Edinburgh

Scotfot: /* Introduction */

2015-02-21T21:33:06Z

Introduction

← Older revision		Revision as of 22:33, 21 February 2015
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	The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.		The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.

	[[File:RiverNorthEskExcursionMap.jpg\|300px\|thumbnail~~\|center~~\|River North Esk - excursion map]]		[[File:RiverNorthEskExcursionMap.jpg\|300px\|thumbnail\|River North Esk - excursion map]]

	==== 1. Polton Bridge: Landslide, Glacial Deposits ====		==== 1. Polton Bridge: Landslide, Glacial Deposits ====

Scotfot: /* Introduction */

2015-02-21T21:32:40Z

Introduction

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	The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.		The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.

	[[File:RiverNorthEskExcursionMap.jpg\|~~600px~~\|thumbnail\|center\|River North Esk - excursion map]]		[[File:RiverNorthEskExcursionMap.jpg\|300px\|thumbnail\|center\|River North Esk - excursion map]]

	==== 1. Polton Bridge: Landslide, Glacial Deposits ====		==== 1. Polton Bridge: Landslide, Glacial Deposits ====

Scotfot: /* Introduction */

2015-02-21T21:32:13Z

Introduction

← Older revision		Revision as of 22:32, 21 February 2015
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	The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.		The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.

			[[File:RiverNorthEskExcursionMap.jpg\|600px\|thumbnail\|center\|River North Esk - excursion map]]

	==== 1. Polton Bridge: Landslide, Glacial Deposits ====		==== 1. Polton Bridge: Landslide, Glacial Deposits ====

Scotfot at 20:59, 21 February 2015

2015-02-21T20:59:00Z

Scotfot at 20:53, 21 February 2015

2015-02-21T20:53:46Z

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	The northern part of the excursion starts from the north side of the river by Pollon Bridge (NT 288 648). The path on the west bank skirts the head scarp of the huge landslide of 1979 (Baird and Smellie. 1980). The top part of the landslide is sand and gravel in which several rock types. including andesites and basalts, can be recognised as originating from the Pentland Hills. The bottom third of the slope is boulder clay.		The northern part of the excursion starts from the north side of the river by Pollon Bridge (NT 288 648). The path on the west bank skirts the head scarp of the huge landslide of 1979 (Baird and Smellie. 1980). The top part of the landslide is sand and gravel in which several rock types. including andesites and basalts, can be recognised as originating from the Pentland Hills. The bottom third of the slope is boulder clay.



	==== 2. Maiden Castle: Meander, Earthwork ====		==== 2. Maiden Castle: Meander, Earthwork ====

Scotfot: /* 6. Old Roslin Powder Mill: Decalcified Sandstone */

2015-02-21T20:51:07Z

6. Old Roslin Powder Mill: Decalcified Sandstone

← Older revision		Revision as of 21:51, 21 February 2015
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	The southern part of the excursion starts at the gates of the Old Roslin Powder Mill, the area surrounding which is a country park supervised by Midlothian District Council. The gates are at the sharp bend on the B7003 below Roslin village (NT 273 633). On the right of the track through the Old Powder Mill are several embayments cut into the sandstone to provide secure and separate sites for the various buildings connected with the manufacture of gunpowder. In the walls of many of these embayments considerable decalcification of the sandstone has taken place, possibly due to acid water from peat banks on the high ground beyond running down the steep faces (Sinclair 1794). The basal portion of these sandstones contains fragments of the underlying mudstone, bands of small pebbles and, in several places, plant fossils such as Calamites.		The southern part of the excursion starts at the gates of the Old Roslin Powder Mill, the area surrounding which is a country park supervised by Midlothian District Council. The gates are at the sharp bend on the B7003 below Roslin village (NT 273 633). On the right of the track through the Old Powder Mill are several embayments cut into the sandstone to provide secure and separate sites for the various buildings connected with the manufacture of gunpowder. In the walls of many of these embayments considerable decalcification of the sandstone has taken place, possibly due to acid water from peat banks on the high ground beyond running down the steep faces (Sinclair 1794). The basal portion of these sandstones contains fragments of the underlying mudstone, bands of small pebbles and, in several places, plant fossils such as Calamites.

			==== 7. Hare Craig: Upper Limestone Group ====

	~~7. Hare Craig: Upper Limestone Group~~		The track crosses the North Esk on a wooden bridge (NT 266 621) from which can be seen a superb section of Upper Limestone Group sediments on the east bank of the river. Upwards from river level are several cycles of sandstone and mudstone overlain by a fireclay some 3 m thick. Massive sandstones have channelled into the top of the fireclay and continue upwards for to m to the viewpoint of Hare Craig on top of the cliff. Leaving the river just beyond the bridge, the path goes up the steep slope of the south bank to join the track of the old Eskbank to Penicuik railway which forms the rest of the route to Penicuik.

	The track crosses the North Esk on a wooden bridge (NT 266 621) from which can be seen a superb section of Upper Limestone Group sediments on the east bank of the river. Upwards from river level are several cycles of sandstone and mudstone overlain by a fireclay some 3 m thick. Massive sandstones have channelled into the top of the fireclay and continue upwards for to m to the viewpoint of Hare Craig on top of the cliff. Leaving the river just beyond the bridge, the path goes up the steep slope of the south bank to join the track of the old Eskbank to Penicuik railway which forms the rest of the route to Penicuik.

	==== 8. Hare Craig to Firth Viaduct: Castlecary Limestone, Roslin Sandstone ====		==== 8. Hare Craig to Firth Viaduct: Castlecary Limestone, Roslin Sandstone ====

← Older revision		Revision as of 21:59, 21 February 2015
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	By W. Baird. From: Lothian geology and excursion guide. Edited by A.D. McAdam and E.N.K. Clarkson. 1996		[[File:Lothian Geology cover.jpg\|thumb\|100px\|right\|[http://www.edinburghgeolsoc.org/p_sales.html#lothiangeology Buy the book]]]
			'''By W. Baird. From: Lothian geology and excursion guide. Edited by A.D. McAdam and E.N.K. Clarkson. 1996'''

	O.S. 1:50000 Sheet 66 Edinburgh		O.S. 1:50000 Sheet 66 Edinburgh
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	At the end of the last ice age, torrential meltwater from a decaying ice-sheet lying between the Moorfoot Hills and the Pentland Hills, cut deep gorges through glacial deposits and into the underlying rocks as it rushed to the sea. The gorge of the River North Esk between Polton and Roslin cuts deep into the Passage Group rocks known locally as the Roslin Sandstone, and further upstream there are fine exposures in the sandstones of the Upper Limestone Group and the Roslin Sandstone (Tulloch and Walton 1958, pp. 61-92).		At the end of the last ice age, torrential meltwater from a decaying ice-sheet lying between the Moorfoot Hills and the Pentland Hills, cut deep gorges through glacial deposits and into the underlying rocks as it rushed to the sea. The gorge of the River North Esk between Polton and Roslin cuts deep into the Passage Group rocks known locally as the Roslin Sandstone, and further upstream there are fine exposures in the sandstones of the Upper Limestone Group and the Roslin Sandstone (Tulloch and Walton 1958, pp. 61-92).

	The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion~~. Lowland and Eastern Scottish buses serve Polton. Roslin and Penicuik~~.		The whole excursion, along the River North Esk from Potton to Penicuik, makes a good day, or it can be split into two half day excursions, with Roslin as the mid-point. Rights of way beside the river exist for the whole length of the excursion.

	==== 1. Polton Bridge: Landslide, Glacial Deposits ====		==== 1. Polton Bridge: Landslide, Glacial Deposits ====

	The northern part of the excursion starts from the north side of the river by ~~Pollon~~ Bridge (NT 288 648). The path on the west bank skirts the head scarp of the huge landslide of 1979 (Baird and Smellie. 1980). The top part of the landslide is sand and gravel in which several rock types. including andesites and basalts, can be recognised as originating from the Pentland Hills. The bottom third of the slope is boulder clay.		The northern part of the excursion starts from the north side of the river by Polton Bridge (NT 288 648). The path on the west bank skirts the head scarp of the huge landslide of 1979 (Baird and Smellie. 1980). The top part of the landslide is sand and gravel in which several rock types. including andesites and basalts, can be recognised as originating from the Pentland Hills. The bottom third of the slope is boulder clay.

	==== 2. Maiden Castle: Meander, Earthwork ====		==== 2. Maiden Castle: Meander, Earthwork ====
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	==== 3. Hawthornden Castle: Gorge in Roslin Sandstone ====		==== 3. Hawthornden Castle: Gorge in Roslin Sandstone ====

	Upstream, south-west from Hawthornden Castle, once the home of the poet Drummond (Macgibbon and Ross 1887), the North Esk runs through a 1·5 km long gorge. From a point about 100 m downstream of Hawthornden Castle, it is possible to leave the path when the water is low and wade up the gorge, but once this route is commenced one must ~~continue~~ to the end of the gorge or return to the starting point. Should one venture by this way, then from the riverside just 100 m upstream from Hawthornden Castle can be seen the highest cliff section in the whole excursion. Sheer cliffs of a beautiful rose-red sandstone rise abruptly from the north bank of the river to a height of 30 m, stretching for over 100 m along the gorge. Massive posts of sandstone in this ~~section~~ show very fine examples of current-bedding. Along the bottom of the gorge the river has scoured out the softest parts of the bedrock to form pot holes, undercuts and deep narrow channels.		Upstream, south-west from Hawthornden Castle, once the home of the poet Drummond (Macgibbon and Ross 1887), the North Esk runs through a 1·5 km long gorge. From a point about 100 m downstream of Hawthornden Castle, it is possible to leave the path when the water is low and wade up the gorge, but once this route is commenced one must continue to the end of the gorge or return to the starting point. Should one venture by this way, then from the riverside just 100 m upstream from Hawthornden Castle can be seen the highest cliff section in the whole excursion. Sheer cliffs of a beautiful rose-red sandstone rise abruptly from the north bank of the river to a height of 30 m, stretching for over 100 m along the gorge. Massive posts of sandstone in this section show very fine examples of current-bedding. Along the bottom of the gorge the river has scoured out the softest parts of the bedrock to form pot holes, undercuts and deep narrow channels.

	Alternatively, superb geological and historical views of Hawthornden Castle can be seen from the cliff top high on the west bank of the river. By following the path which gently descends to just above the river, beautiful exposures of the pinkish red Roslin Sandstone can be seen. ~~Currentbedding~~, apparent everywhere, often on a large scale, shows that this sandstone was laid down in a high energy, continually changing river environment. Bands of pebbles at the base of this pebbly, gritty sandstone indicate each surge of current.		Alternatively, superb geological and historical views of Hawthornden Castle can be seen from the cliff top high on the west bank of the river. By following the path which gently descends to just above the river, beautiful exposures of the pinkish red Roslin Sandstone can be seen. Current-bedding, apparent everywhere, often on a large scale, shows that this sandstone was laid down in a high energy, continually changing river environment. Bands of pebbles at the base of this pebbly, gritty sandstone indicate each surge of current.

	==== 4 and 5. Roslin Gorge: Roslin Sandstone, Tufa ====		==== 4 and 5. Roslin Gorge: Roslin Sandstone, Tufa ====
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	==== 6. Old Roslin Powder Mill: Decalcified Sandstone ====		==== 6. Old Roslin Powder Mill: Decalcified Sandstone ====

	The southern part of the excursion starts at the gates of the Old Roslin Powder Mill, the area surrounding which is a country park supervised by Midlothian District Council. The gates are at the sharp bend on the B7003 below Roslin village (NT 273 633). On the right of the track through the Old Powder Mill are several embayments cut into the sandstone to provide secure and separate sites for the various buildings ~~connected~~ with the manufacture of gunpowder. In the walls of many of these embayments considerable decalcification of the sandstone has taken place, possibly due to acid water from peat banks on the high ground beyond running down the steep faces (Sinclair 1794). The basal portion of these sandstones contains fragments of the underlying mudstone, bands of small pebbles and, in several places, plant fossils such as Calamites.		The southern part of the excursion starts at the gates of the Old Roslin Powder Mill, the area surrounding which is a country park supervised by Midlothian District Council. The gates are at the sharp bend on the B7003 below Roslin village (NT 273 633). On the right of the track through the Old Powder Mill are several embayments cut into the sandstone to provide secure and separate sites for the various buildings connected with the manufacture of gunpowder. In the walls of many of these embayments considerable decalcification of the sandstone has taken place, possibly due to acid water from peat banks on the high ground beyond running down the steep faces (Sinclair 1794). The basal portion of these sandstones contains fragments of the underlying mudstone, bands of small pebbles and, in several places, plant fossils such as ''Calamites''.

	==== 7. Hare Craig: Upper Limestone Group ====		==== 7. Hare Craig: Upper Limestone Group ====

	The track crosses the North Esk on a wooden bridge (NT 266 621) from which can be seen a superb section of Upper Limestone Group sediments on the east bank of the river. Upwards from river level are several cycles of sandstone and mudstone overlain by a fireclay some 3 m thick. Massive sandstones have channelled into the top of the fireclay and continue upwards for to m to the viewpoint of Hare Craig on top of the cliff. Leaving the river just beyond the bridge, the path goes up the steep slope of the south bank to join the track of the old Eskbank to Penicuik railway which forms the rest of the route to Penicuik.		The track crosses the North Esk on a wooden bridge (NT 266 621) from which can be seen a superb section of Upper Limestone Group sediments on the east bank of the river. Upwards from river level are several cycles of sandstone and mudstone overlain by a fireclay some 3 m thick. Massive sandstones have channelled into the top of the fireclay and continue upwards for 10 m to the viewpoint of Hare Craig on top of the cliff. Leaving the river just beyond the bridge, the path goes up the steep slope of the south bank to join the track of the old Eskbank to Penicuik railway which forms the rest of the route to Penicuik.

	==== 8. Hare Craig to Firth Viaduct: Castlecary Limestone, Roslin Sandstone ====		==== 8. Hare Craig to Firth Viaduct: Castlecary Limestone, Roslin Sandstone ====
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	==== 10 and 11. Dalmore Mill: Roslin Sandstone ====		==== 10 and 11. Dalmore Mill: Roslin Sandstone ====

	Rejoin the track just downriver from the Dalmore Mill (10), pass through the tunnel under the B7026 and cross to the west bank of the North Esk by the old railway bridge which starts just beyond the tunnel. On the opposite side of the river, poorly exposed sandstone with almost horizontal bedding can be seen (11). Beyond, sandstones with a westward dip of 15° gradually become horizontal further ~~upstream~~. In a rapidly eroding bank 6 m high, one can see an exposure of sandstones and mudstones which have almost certainly slumped from further up the bank.		Rejoin the track just downriver from the Dalmore Mill (10), pass through the tunnel under the B7026 and cross to the west bank of the North Esk by the old railway bridge which starts just beyond the tunnel. On the opposite side of the river, poorly exposed sandstone with almost horizontal bedding can be seen (11). Beyond, sandstones with a westward dip of 15° gradually become horizontal further upstream. In a rapidly eroding bank 6 m high, one can see an exposure of sandstones and mudstones which have almost certainly slumped from further up the bank.

	==== 12. Glencorse Barracks: Sandstone Quarry ====		==== 12. Glencorse Barracks: Sandstone Quarry ====
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	Continue beyond the Penicuik sewage works, across the bridge at Harper's Brae (NT 245 605) and take the walkway upstream on the east bank of the river to a point 60 m upstream from the wooden walkway bridge. Exposed just at water level on the east bank. is a limestone correlated with the Calmy Limestone. Return to the bridge at Harper's Brae and take the Kirkhill Road which rises steeply into Penicuik.		Continue beyond the Penicuik sewage works, across the bridge at Harper's Brae (NT 245 605) and take the walkway upstream on the east bank of the river to a point 60 m upstream from the wooden walkway bridge. Exposed just at water level on the east bank. is a limestone correlated with the Calmy Limestone. Return to the bridge at Harper's Brae and take the Kirkhill Road which rises steeply into Penicuik.

			== At all times follow: [http://www.outdooraccess-scotland.com/the-act-and-the-code/introduction The Scottish Access Code]and [http://www.geologistsassociation.org.uk/downloads/Code%20of%20conduct/Code%20for%20fieldwork%20combined.pdf Code of Conduct for Fieldwork] ==


			[[category:5. Midland Valley of Scotland]]