Holyrood Park, Edinburgh - Geowalks

Earth Science Outdoors 

Teachers' Guide: CfE 

Level 3/4 

Lower Secondary 

Holyrood Park, Edinburgh 

Highlights 

• Contrasting sedimentary 

and igneous rocks 

• Glacial erosion – crag and 

tail, glacial erratics 

• Eroded volcano, lava flows 

and crater rocks 

• Links between geology, 

landscape, land use, 

building stones and human 

settlement 

The Scottish Earth Science Education Forum 

(SESEF) is an association of educators and scientists 

established to promote understanding of planet Earth 

in Scottish schools and colleges. 

Membership of SESEF is free – visit 

www.sesef.org.uk for further information. 

Scottish Earth Science Education Forum, Grant 

Institute, School of GeoSciences, University of 

Edinburgh, West Mains Road, Edinburgh EH9 3JW 

0131 651 7048 

Teachers' Guide: CfE level 3/4 Holyrood Park, Edinburgh 27/10/09 1

Table of Contents 

Introduction.......................................................................................................................................................2 

Using this guide...........................................................................................................................................2 

The geological background..........................................................................................................................2 

Glossary......................................................................................................................................................3 

Links with the curriculum.............................................................................................................................4 

Sources of further information & support.....................................................................................................5 

Location maps, directions & local facilities........................................................................................................6 

Safety & conservation.......................................................................................................................................6 

Suggested pre- and post-visit activities.............................................................................................................7 

Suggested localities..........................................................................................................................................9 

Introduction (start at NT 2701 7370)............................................................................................................9 

Location 1: Edinburgh's landscape NT 2715 7370.......................................................................................9 

Location 2: Camstone Quarry NT 2706 7342............................................................................................10 

Location 3: St Anthony's Well - erratic boulder & lava flow NT 2752 7365.................................................11 

Location 4: The Dasses – close up view of basalt NT 2747 7363..............................................................12 

Location 5: Hunter's Bog – wetland and view of Arthur's Seat NT 2725 7339...........................................12 

Location 6: Scree slope NT 2729 7282......................................................................................................14 

Location 7: Hutton's Section – sandstone and dolerite NT 2719 7284.......................................................15 

Location 8: View of the Castle crag and tail NT 2679 7311........................................................................16 

Acknowledgements.........................................................................................................................................16 

Evaluation & Feedback Form..........................................................................................................................17 

Introduction 

Arthur's Seat and Salisbury Crags are prominent natural features within the heart of the city of Edinburgh, 

easily accessible and with many themes that can encourage cross-curricular learning and exploration. This is 

a natural laboratory for making connections between the underlying rocks and the shape of the landscape, 

and the way in which people have used the land and the rocks. Many of these themes are directly 

transferable to other areas of central Scotland. 

Using this guide 

This Teachers' Guide has been produced by the Earth Science Outdoors project, which is developing 

resources to encourage and support outdoor learning within the Curriculum for Excellence (CfE). All our 

resources are available for free from our website, and teachers are welcome to use and adapt them. 

This guide is written to as a resource to aid teachers in leading a field trip. It cannot be a complete package – 

you'll need to do a site visit, carry out a risk assessment and choose localities and activities that are suitable 

for your group and the theme that you want to explore. You might want to prepare material for pupils. The 

text and figures in this guide are available as separate files from www.sesef.org.uk, where you will also find a 

gpx file that can be downloaded to a handheld GPS unit to help you find the suggested localities. 

We welcome feedback, suggestions and examples of how you have used the guide. Contact us through the 

SESEF website www.sesef.org.uk. Throughout the guide underlined words are linked to the glossary on 

page 3. 

The geological background 

Figure 1: timeline 


The Arthur's Seat volcano erupted around 342 million years 

ago, during the Carboniferous Period (see timeline, Figure 

1). At that time Scotland was located south of the equator, 

enjoying a sub-tropical climate. On the surrounding flat 

muddy plains and lagoons close to the sea new 

sedimentary rocks were forming. These include 

mudstones, sandstones and later coal and limestone, and 

they form the bulk of the bedrock beneath the Edinburgh 

area. There is a strong contrast in the properties of the 

easily eroded sedimentary rocks and the large masses of 

more resistant igneous rocks; it is this contrast between 

rock types that is responsible for the varied landscape of 

central Scotland. 

Figure 2: Reconstruction of the Carboniferous volcanic 

environment in the Edinburgh area (from “Edinburgh's Volcano” 

leaflet published by the Edinburgh Geological Society). 

The Arthur's Seat volcano had several vents where red-hot, 

mobile, basaltic magma came to the surface and spread 

out across the area as thin lava flows. These vents include 

the heavily eroded Castle Rock plug, where hundreds of 

metres of volcanic rock have been removed, and the 

better-preserved Arthur's Seat vents where lava flows and 

rocks formed within the crater are still visible. 

Later, Salisbury Crags formed when more magma 

approached the surface, but this time it got trapped 

underground and spread sideways to create a horizontal 

layer (or sill) of more slowly cooled dolerite rock. Hutton's 

Section is a key site at the foot of Salisbury Crags where 

the uneven junction between the dolerite and the 

underlying sandstone is exposed. James Hutton used this 

to illustrate his theory of an ancient Earth where natural 

forces were responsible for the creation and destruction of 

rocks on unimaginably long timescales. 

The key features of the site are: 

• The contrast between sedimentary and igneous 

rocks is responsible for the shape of the 

surrounding land. 

• A variety of igneous rocks, allowing understanding 

of how igneous rocks are created from intrusions, 

lava flows and explosive volcanic eruptions. 

• Glacial landscapes, including views of the Castle 

Rock crag and tail and glacial scoops. 

• Land use influenced by bedrock, contrast between 

built-up areas and hunting / farming land. Use of 

local stones in building. 

Glossary 

Basalt the most common type of lava; finegrained, 

dense and dark in colour. 

Carboniferous Period geological period 299- 

359 million years ago, when North Berwick's 

rocks formed. 

Dolerite a medium-grained equivalent to 

basalt, formed when magma cools 

underground. Salisbury Crags is made of 

dolerite. 

Fine-grained description of igneous rock with 

small crystals, which has cooled quickly 

Igneous rock members of this family of rocks 

have all crystallised from molten magma or 

lava 

Intrusion cooled body of magma trapped 

underground 

Lava / magma molten rock that has come 

from deep beneath the surface. Magma 

becomes lava when it is erupted at the 

surface 

Plug solid interior of the volcano, where 

magma beneath the vent has cooled and 

solidified. 

Sedimentary rock forms from loose 

sediment that accumulates at the surface and 

gets buried, compacted and cemented to 

form solid rock 

Vent the crater area of a volcano, where the 

magma comes to the surface. The vent lies 

above the plug. 

Volcanic ash fragmented material that has 

been blasted out of a volcanic vent during an 

explosive eruption. 

More definitions online at 

http://geology.com/geology-dictionary.shtml 


Links with the curriculum 

Holyrood Park has many opportunities for cross-curricular themes. You will find a wide range of suggested 

activities in this guide. Teachers and group leaders will need to select localities and activities that form a 

suitable excursion, by referring to the relevant Curriculum for Excellence outcomes here, and making a 

exploratory visit. We would recommend not trying to accomplish too much, and focus on forming a coherent 

whole rather than just a series of localities. 

Curriculum for Excellence Outcomes How the outcomes can be addressed in this area 

SOC 3-07a Having investigated processes 

which form and shape landscapes, I can 

explain their impact on selected 

landscapes in Scotland, Europe and 

beyond. 

SOC 4-07a I can explain how the 

interaction of physical systems shaped 

and continue to shape the Earth's surface 

by assessing their impact on contrasting 

landscape types. 

SCN 3-17a Through evaluation of a range 

of data, I can describe the formation, 

characteristics and uses of soils, minerals 

and basic types of rocks. 

MNU 3-11a I can solve practical problems 

by applying my knowledge of measure, 

choosing the appropriate units and degree 

of accuracy for the task and using a 

formula to calculate area or volume when 

required. 

SOC 4-14a I can use specialised maps and 

geographical information systems to 

identify patterns of human activity and 

physical processes. 

SOC 4-10a I can develop my understanding 

of the interaction between humans and the 

environment by describing and assessing 

the impact of human activity on an area. 

SOC 3-13a By comparing settlement and 

economic activity in two contrasting 

landscapes, I can reach conclusions about 

how landscapes influence human activity. I 

can explain my findings clearly to others. 

SOC 4-10c Having studied an economic 

activity, I can explain its development and 

assess the impact of change within its 

locality and beyond. 

Very clear example of how the variety in local rocks and their 

contrasting resistance to erosion is responsible for the local 

landscape, and how the direction of ice flow during the Ice 

Ages has shaped the local area. Pupils can discover scree 

slopes and appreciate that Arthur's Seat and Salisbury 

Crags are continuing to erode. 

Explore processes in the past that have created and eroded 

different rock types – volcanic activity, erosion and 

deposition. Classroom activities before or after a visit could 

consider how Edinburgh's landscape differs from other 

areas. 

Hands-on exploration of local rock types, including igneous 

and sedimentary rocks. Collect evidence from the Camstone 

Quarry of the environment in the past and how the local 

sandstone has formed. Examine a lava flow and rocks from 

the crater of the volcano. 

Opportunities to measure the angle of slopes and estimate 

the height of the Castle Rock volcano. Calculate the number 

of gas bubbles in a lava flow and estimate the proportion of 

gas to lava. 

Use Google Earth, British Geological Survey online maps, 

etc in advance of a visit to discover links between bedrock 

and scenery. 

There is a long history of humans using the park, including 

remains of Iron Age forts on top of the hills. People have 

altered the area by removing trees and draining low ground; 

rock has been removed – sandstone used for building and 

dolerite for roads ('cobbles'). 

Hill tops were important, easily-defended sites of early 

settlement; Early settlers farmed on the well-drained slopes; 

Later when the low ground around the park was drained it 

was ideal for development of the city. 

Two disused quarries are visited and the rock types can be 

compared. Further research after the trip can explore what 

the stone was used for – sandstone for building and dolerite 

for road stone – and other sources of stone in Edinburgh in 

historical times and the present day. 


Sources of further information & support 

The Edinburgh Geological Society publish leaflets on the local geology, including “Discovering Edinburgh's 

Volcano” ISBN 0-904440-12-5. www.edinburghgeolsoc.org. 

For a general introduction to the geology of this area we recommend: 

McAdam, D (2003), “Edinburgh & West Lothian, a landscape fashioned by geology”, Scottish Natural 

Heritage, ISBN 1-85397-327-0. Available to view or download online at 

http://www.snh.gov.uk/pubs/detail.asp?id=45. 

Clarkson, E & Upton, B (2006), “Edinburgh Rock: the geology of Lothian”, Dunedin Academic Press, ISBN 1- 

903765-39-0. 

The British Geological Survey poster “Edinburgh: Born of fire and ice cradle of modern geology” is available 

to purchase from the BGS Bookshop http://shop.bgs.ac.uk/Bookshop/product.cfm?id=VPEDIN. 

Our Dynamic Earth takes you and your pupils on an extraordinary and enlightening educational journey of 

discovery. You’ll travel back in time, be shaken by volcanoes, feel the chill of polar ice, get caught in tropical 

rainstorms, journey to the centre of the Earth & deliberate the future of our dynamic planet. 

Combine a visit round the galleries with one of twenty-two fantastic activities. With amazing handling 

specimens, the latest smart board and inter-active technology and awe inspiring classrooms, and a 

dedicated education team, the education programme offers an immersive, multi-sensory experience that will 

stimulate pupils’ imaginations and bring the curriculum to life. www.dynamicearth.co.uk. 0131 550 7800. 

Historic Scotland Ranger Service has a flexible approach to working with schools, offering a programme 

of structured activities and self-led visits linked to curricular guidelines. Rangers will be pleased to work with 

teachers to develop tailored activities suitable for individual classes. 0131 652 8150. 

www.historic-scotland.gov.uk/index/learning/education_unit/ranger.htm 

Geowalks guided tours with geologist Angus Miller are available for school & university parties, exploring a 

range of themes such as volcanoes, plate tectonics, and the forces that have shaped the landscape. 

www.geowalks.co.uk 0131 555 5488. 

The SESEF website www.sesef.org.uk offers various resources and links. You can ask us to send you a free 

simplified Geological Map of Scotland. This Teachers' Guide can be downloaded from our website, and all 

the images are available as jpg files for you to print or project. We are also keen to share any supporting 

resources that you develop, and other ideas or resources that you have – send them to us and we'll post 

them on the web. 


Location maps, directions & local facilities 

Figure 3: Location maps: www.ordnancesurvey.co.uk/getamap. Image produced from Ordnance Survey's Get-a-map service. 

Image reproduced with permission of Ordnance Survey and Ordnance Survey of Northern Ireland. 

Holyrood Park is close to Edinburgh City Centre and accessible by public transport – for details visit 

www.transportdirect.info, you can use the Scottish Parliament postcode EH99 1SP as the destination. 

Minibuses and coaches entering Holyrood Park require permission from Historic Scotland, which can be 

obtained by contacting the Ranger Service on 0131 652 8150. There is no charge for educational groups. 

There are two main entry points to the park (red arrows in figures 3 and 7): 

1. Holyrood Palace / Scottish Parliament / Our Dynamic Earth. These are all close together at the foot of the 

Royal Mile and Holyrood Road. You can ask the Ranger Service (see above) for permission to park coaches 

and minibuses in the Broad Pavement car park next to Holyrood Palace. There are safe coach drop off 

points around Holyrood Park, at Holyrood Palace and the Scottish Parliament, Horse Wynd and Our 

Dynamic Earth, Holyrood Road. Metered minibus and coach parking is available at Regent Road. 

2. Holyrood Park Road, near the Commonwealth Pool. There is meter parking for cars and minibuses and 

plenty of space for coach drop offs along the road. 

There are no public toilets in the Park, however there are publicly accessible toilets available for free at 

Historic Scotland Ranger Service Education Centre (see map, Figure 7), Holyrood Palace, the Scottish 

Parliament (need to go through security check) and Our Dynamic Earth. 

Safety & conservation 

Holyrood Park is visited by thousands of people every year and is generally safe. The paths are good, 

although rough in places. There are cliffs and steep slopes but the most dangerous of these are not 

encountered while following the route described below. The return route along the base of Salisbury Crags 

requires care, and if it is not suitable for your group you can walk by the road instead. The main hazards that 

need to be considered are: 

Hazard What might happen Suggested control measures 

Road crossing Collision with vehicle Use safe crossing points: there is a pedestrian crossing on 

the Queens Drive near Holyrood Palace and traffic islands 

at roundabouts. 

Weather conditions – areas of 

the park can be very exposed 

Exposure to cold / wet / 

heat 

Rough paths Twisted ankle Adequate footwear. 

Steep grassy paths Injuries due to slipping or 

falling 

Pre-trip instructions to bring warm waterproof clothing and 

adequate footwear. Group leaders carry spare clothing. 

Students warned not to run ahead down slopes. 

Sheer drops Injuries due to falling Plan route that avoids exposure to sheer drops. All keep 2 

metres back from cliff tops. 


The park is cared for by the Historic Scotland Ranger Service who will be happy to advise about 

conservation issues. The whole area is an Site of Special Scientific Interest, designated for geology, 

grassland and vascular plants, and a Scheduled Ancient Monument. The use of geological hammers is not 

allowed and collecting of samples – even loose material – is not permitted. You should follow the Scottish 

Fossil Code and the Scottish Outdoor Access Code, both published by Scottish Natural Heritage. 

Suggested pre- and post-visit activities 

• Explore Scotland's rocks and your local rocks. Compare satellite images e.g. Google Earth with a local 

geological map, which are available online from the British Geological Survey, 

http://www.bgs.ac.uk/education/geology_of_britain/home.html although probably in more detail than you 

need, or use the simplified version in “Edinburgh & West Lothian, a landscape fashioned by geology” 

available online at 

http://www.snh.org.uk/publications/on-line/geology/edinburgh_wlothian/map.asp 

• Experiment to discover the resistance of different rock types to erosion. This can be done using a good 

quality rock file, e.g. a tile file, to scratch different rocks held over a sheet of paper – you should find that 

sedimentary rocks such as sandstone crumble more easily than igneous rocks. Or put small samples in a 

strong plastic bottle and give it a good shake. 

Figure 4: the result of vigorous filing of a piece of sandstone 

with a tile file for less than 30 seconds. Sand grains in 

sandstone are cemented together and easy to separate. If 

you do the same to a piece of basalt, not much happens. 

The file is a model for glacial erosion of Edinburgh's 

landscape. 

Figure 5: pieces of sandstone that have been shaken in a 

strong plastic bottle. 

• Explore geological time and place the Carboniferous Period and the Ice Ages relative to events such 

dinosaur extinction. See the Earth Science Outdoors document “Activities for all ages” for some ideas. 

• Find out about modern volcanoes, especially 'red' 

basaltic lava flows e.g. Hawaii, Iceland, Mount 

Etna. Learn the parts of volcanoes – magma 

chamber, crater, lava flows, ash. Take one of the 

virtual walks up a modern volcano at Stromboli 

online www.swisseduc.ch/stromboli/ The walk 

up Nyiragongo, DR Congo (Figure 6) in particular 

gives a good impression of how Arthur's Seat 

might have erupted. 

• Combine with a tour / workshop at Our Dynamic Earth. 

Figure 6: virtual walk on Nyiragongo, showing modern 

conditions similar to the eruption of Arthur's Seat. 


Figure 7: Outline map of Holyrood Park, showing the localities described in the text. Geology based on the “Edinburgh's 

Volcano” leaflet published by the Edinburgh Geological Society. 


Suggested localities 

Introduction (start at NT 2701 7370) 

The localities described follow a route starting beside Holyrood Palace and walking from north to south 

through Hunter's Bog. The entire walk is around 4 km and will take at least 2 hours, more if you tackle 

some of the suggested activities. There are 8 localities, although not all will be suitable for every 

group. From the final location at Salisbury Crags you can complete a clockwise circuit back to the start 

point along either the Radical Road path (with a steep slope alongside and a steep descent to join the 

road at the end) or take the road at the foot of the Salisbury Crags scree slopes. Or you can arrange to 

be picked up on Holyrood Park Road near the Commonwealth Pool. 

Alternatively you can start your excursion at the other main entrance to the park, at Holyrood Park 

Road, and visit locations 6, 7 and 8 in any order. This involves a shorter walking distance while still 

seeing most of the main features. 

Location 1: Edinburgh's landscape NT 2715 7370 

Stop anywhere in the vicinity of Holyrood 

Palace with views of Salisbury Crags and 

Calton Hill. The shape of the landscape 

around you is controlled by the contrasting 

properties of the local sedimentary and 

igneous rocks. Beneath the Palace and the 

surrounding low ground are sedimentary 

rocks of early Carboniferous age. These 

rocks are not visible, because they have 

been heavily eroded and are covered by 

later deposits. The sedimentary rocks are 

separated by fault lines from the much more 

visible igneous rocks that make Salisbury 

Crags and Calton Hill, and all the other hills 

of Edinburgh. 

Some questions to lead discussion: 

Figure 8: Contrast between the flat parkland behind Holyrood Palace, 

and the slope of Salisbury Crags. Arrow indicates a good stopping point 

on the path that leads eastwards around the back of Salisbury Crags. 

What can you see around you? [Cliffs, high ground, low ground, rocks, grass, buildings, hills, 

monuments.] 

Why is Arthur's Seat a hill? [Volcano... hard rock] 

Why is there flat, low ground around the Palace? [Soft rock (sandstone) that has been eroded away. 

Glaciation – ice sheets have removed the less resistant rock]. 

You may also want to at this stage introduce the idea of the direction the ice was moving in, which is 

responsible for the shape of the hills. This is not the best place to see the steep west-facing slopes and more 

gentle eastern slopes of the Castle Rock and Calton Hill, but pupils may already be aware of the shape of 

the Castle Rock and the Royal Mile. One associated feature that can be seen here is the 'glacial scoop' in 

front of Salisbury Crags, where the ice has eroded more deeply into the surrounding sedimentary rocks as it 

squeezed past the Crags. 

Suggested activities: 

1. If you haven't already done this as a pre-visit activity (see above) this is a good place to experiment 

to discover the resistance of different rock types to erosion. A good quality rough file (e.g. a tile file) 

will easily carve a piece of sandstone, breaking off grains that can be collected on a sheet of white 

paper. In contrast, a typical local igneous rock will barely be scratched by the file. N.B. it is illegal to 

damage the Park's rocks, so bring your own samples with you – freely available from most beaches in 

central Scotland! 

2. Pace out a Geological Timeline as you walk into the park, and put the geological events that have 

shaped the local scenery (including volcanic eruptions and glaciation) into the context of the 4,600 

million year history of the Earth. See accompanying “Activities for all ages” document for more 

information. 


Proceed to the left towards Hunter's Bog and take the grassy track on the left that traverses the 

eastern slope of Salisbury Crags. The Camstone Quarry is half-way up the slope, surrounded by gorse 

bushes and grassed-over spoil heaps. 

Location 2: Camstone Quarry NT 2706 7342 

The history of this quarry is not well recorded, but it is believed to have been worked during the 17 th century. 

It is one of more than 20 quarries of various sizes within or close to the city of Edinburgh, where local 

sandstone was quarried for building stone. Many of the other quarries are filled in, so the exposed layers in 

the Camstone Quarry give a rare glimpse of Edinburgh's sandstone layers. 

On entering the quarry, the main face of interest is ahead on the righthand (north) side. The quarry face is 

potentially unstable and should not be approached. Examine the fallen boulders in front of the quarry 

face. Note the contrast in shape between blocks that have recently been dislodged from the face and the 

rounded and smoothed boulder at the entrance to the quarry, which has been carried here by ice. 

Figure 9: Face of the Camstone Quarry. From a safe 

distance different sedimentary layers can be identified. The 

overhang 2/3 of the way up the face shows where a softer 

layer of mudstone has been worn away. 

Figure 10: Desiccation cracks on surface of a fallen 

boulder. This indicates a period during the formation of the 

rock when the sediment at the surface was exposed and 

dried out. 

In the fallen boulders are two clues to the environment when the sandstone was being formed: sets of ripples 

and desiccation cracks. The ripples resemble those on sandy beaches and suggest shallow water and the 

transport of sediment by currents. In one block it is possible to pick out a change in the direction of the 

ripples from one layer to the next, which is suggestive of an environment where the current direction changes 

with time. The desiccation cracks show an episode of drying, with the sand and mud being exposed to the 

sun. Put together, we have evidence of a changing environment, with the sand sometimes under water and 

sometimes exposed. This combined with evidence from elsewhere in the local area is interpreted as an 

environment of shallow lagoons in a semi-arid climate. 

Suggested activities: 

Make a labelled sketch of one of the features of the sandstone – layering, ripple marks or desiccation 

cracks. Explain what the feature tells us about the environment when the rock was forming. 

Estimate the height of the cliff. How long would it take to form these layers of sandstone? As a rough 

guide, 5 km of sedimentary rock formed in around 50 million years during the Carboniferous Period, at 

an average of 1 m in 10,000 years. However, sandstone like this probably accumulates quite quickly, 

with long pauses when no new rock forms. 

From the quarry retrace your steps back down to the main path and take the gravel path towards St 

Anthony's Chapel. Location 3 is at St Anthony's Well, which is located on the path beneath the chapel. 


Location 3: St Anthony's Well - erratic boulder & lava flow NT 2752 7365 

As you approach St Anthony's Well there are 

opportunities to observe small scale landscape 

features that mimic the shape of Edinburgh's hills. 

Haggis Knowe on the left of the path has a steep 

western (scarp) face and a gentler, grassy eastern 

(dip) slope with the faint remains of agricultural 

terraces. Contrast the view to the east – steep slopes 

and cliffs around St Anthony's Chapel (Figure 9), with 

the view to the west, where the slopes are more 

gentle and grass-covered. 

Figure 11: Haggis Knowe, showing typical 

glaciated shape of Edinburgh's hills. 

The large, rounded boulder beside the path marks the 

site of St Anthony's Well, a place of pilgrimage for 

centuries. Nowadays the water is piped around the 

corner into St Margaret's Loch, but in living memory 

there was a spring here, and a cup on a chain to allow 

passers-by to quench their thirst. 

This boulder is a glacial erratic, dumped here at the 

end of the last ice age, and a representative of the 

huge volume of rock and sediment transported in the 

ice sheet. The boulder is tough dolerite rock, which 

doesn't match the local bedrock, and has been 

rounded and polished while being transported to here, 

possibly from Corstorphine Hill in west Edinburgh. 

Figure 12: steep west-facing slopes of basalt lava 

in the vicinity of St Anthony's Chapel. 

Figure 13: St Anthony's Well capped by an erratic boulder. 

The remarkably rounded shape of this boulder suggests that it has been caught up and transported by 

meltwater after the ice melted, which must have been quite an incredible flow of water. 

Behind the boulder the path towards the summit of Arthur's Seat crosses exposed rock. This is the top 

surface of a basalt lava flow, which has been buried and preserved by further volcanic eruptions. So when 

you stand on the basalt today, you are standing on the land surface of around 340 million years ago, when 

red, runny lava flows were produced from local craters. Since the lava formed, the whole layer has been 

tilted from a nearly horizontal postion to the current tilt of around 20º. 

This is the Long Row lava, and originally formed a continuous layer rising gently to its source, which was the 

crater around 1 km above the current position of Edinburgh Castle. Erosion has removed almost all traces of 

this volcanic cone. The Castle Rock is a volcanic plug, the remains of the underground conduit that 

channelled magma towards the surface crater, and finally solidified. 

Suggested activity: 

Estimate, and then measure the angle of the slope of the top of the Long Row. Measuring from the 

horizontal, you should get a result close to 20º. Compare the angle measured using a protractor or 

clinometer on an exposed rock surface with the angle measured on the grass slope using poles and 

string. Which is more accurate? [probably measuring the grassy slope, it is difficult to get a smooth 

representative surface on top of a lava flow.] 

Use trigonometry or sketch a cross section to work out what height the lava would have been above 

the Castle 2.5 km away, if the rock sloped at the same angle all the way. [2500 m × tan 20º = 900 m. 

Note this is not strictly the height of the volcano, as the slope is a later artefact due to tilting of the 

layers. But you are estimating the location of the crater of the Castle volcano, sitting on top of 

hundreds of metres of older rock that has now been eroded.] 


From St Anthony's Well retrace your steps a short distance and take the path on the left towards 

Hunter's Bog. The Dasses are a short distance ahead on your left. 

Location 4: The Dasses – close up view of basalt NT 2747 7363 

The Dasses are a good place to appreciate that 

igneous rocks are crystalline. A close look at the upper 

face of the exposed rock will reveal small, rectangular 

outlines of feldspar crystals, surrounded by pale rock 

which is itself made of crystals too small to see with 

the naked eye. The visible crystals formed first, when 

the magma was cooling slowly and the crystals had 

time to grow. Later, the magma got pushed close to 

the surface and the remaining liquid crystallised 

quickly. 

Suggested activity: 

Measure the angle of slope of the top surface 

of the exposed rock. Is it easier to get a 

consistent measurement here that at location 

2? [it should be, as the surface is much 

smoother. This is not a lava flow, but an 

intrusion, where magma has got trapped below 

ground – intrusions tend to have much 

smoother upper surfaces than lava flows]. 

Figure 14: The Dasses, a ledge of basalt that has withstood 

erosion better than the surrounding layers of sedimentary 

rock. 

Sedimentary rocks are hard to spot around here, but the basalt was originally encased in layers of 

sedimentary rock. They have proved less resistant to erosion so The Dasses are left standing proud of the 

land surface. 

From The Dasses proceed back across Hunter's Bog and proceed along the main path towards 

location 5, beside the pond (Figure 15). 

Location 5: Hunter's Bog – wetland and view of Arthur's Seat NT 2725 7339 

Hunter's Bog is typical of the low-lying areas of Edinburgh, formed 

from the erosion of sedimentary rocks. These low-lying areas had 

poor drainage and many of them were lakes in post-glacial times. 

In 1564 Mary Queen of Scots ordered the creation of an artificial 

loch, and later in Victorian times the bog was drained as part of 

wider improvements that created St Margaret's and Dunsapie 

Lochs and the Queen's Drive. 

The current pond dates from the mid-1990s when the level of the 

main drain was raised to create permanent wetland once again, 

for the benefit of wildlife. 

Suggested Activity: 

This is a good spot to appreciate the structure of the 

Arthur's Seat volcano and identify the different parts – see 

worksheet, next page. 

Follow the path along the valley and up towards the saddle 

between Arthur's Seat and Salisbury Crags. Just before you 

reach the top of the slope, go left and among the long grass 

you'll find rocks that have been washed and bounced down 

from Arthur's Seat. 

Figure 15: Pond in Hunter's Bog with the 

summit of Arthur's Seat behind. 



Location 6: Scree slope NT 2729 7282 

The rock samples here have mostly come from the eroding slopes of Arthur's Seat above. The gulley above, 

called the 'Guttit Haddie', was apparently created during an intense rainstorm on 13 September 1744. 

The scree demonstrates the variety of rocks that form the volcano. The lumpy rocks made of red and green 

particles are agglomerate, from within the Arthur's Seat vent. When the volcano exploded particles of various 

sizes were blasted into the air and fell back to fill the vent. You'll also find grey/black pieces of basalt. 

This is a good place to consider the on-going natural processes of weathering and erosion that are very 

slowly destroying Arthur's Seat. Physical weathering has loosened pieces of bedrock and the processes of 

erosion are moving these pieces downhill and further breaking them up. The extent of vegetation on the 

slope shows that most of the scree slope is old and stable; however there are plenty of fresh pieces lying 

around to demonstrate the on-going process. 


Measure the average size of a representative sample of the rocks at several places on the scree 

slope. What pattern would you expect to find? [in this case, the size of individual rocks gets smaller as 

you go down the slope, because the larger rocks are getting broken up as they proceed downwards. 

However in some scree slopes you find the largest boulders at the bottom as they are able to bounce 

and roll further than smaller rocks.] What's the best way to measure a rock? [one good way is to 

measure the longest dimension.] How do you get a representative sample at each location? [perhaps 

put down a small quadrat and measure every rock within the quadrat?] 

Figure 16: Scree slope below Arthur's Seat, with Hunter's 

Bog and the Firth of Forth in the background. 

Follow the main path through the low point of 

Salisbury Crags and start to descend towards 

the Commonwealth Pool. After 50 m or so, take 

the main track to the right, the Radical Road, 

which skirts the base of Salisbury Crags. 

Immediately turn right again onto a narrow 

grassy path which takes you to Hutton's Section 

(see Figure 18). 

Figure 17: Typical rocks in the scree. The lumpy rocks 

made of red and green fragments are samples of 

agglomerate from the Arthur's Seat vent. Pale grey basalt 

rocks are also present. 

Figure 18: Path to Hutton's Section 


Location 7: Hutton's Section – sandstone and dolerite NT 2719 7284 

Figure 19: Hutton's Section – the information board at lower 

right tells the story of James Hutton and his discovery here. 

Figure 20: Close up of Hutton's Section, showing the 

junction between sandstone and dolerite and the buckled 

section of sandstone that Hutton used as proof that the 

dolerite was emplaced as a liquid . 

At Hutton's Section at the base of Salisbury Crags you can get a close look at some of Edinburgh's important 

rock types, and appreciate the long story of the formation of Edinburgh's rocks. This is a world-famous 

geological site due to its association with James Hutton (1726-1797), the father of modern geology. 


It is a good place to allow students free rein to make their own observations and perhaps a sketch. There are 

some quite clear features that allow the differences between sedimentary and igneous rocks to be explored: 

the sandstone occurs at the base of the cliff (showing layers, variation between sandy and lime-rich layers, 

wearing away more than the dolerite) and the dolerite lies above (coarse surface, some small holes 

(vesicles) = gas bubbles, irregular cracks but no layering). The lower part of the cliff is relatively safe and 

hard hats should not be required; however watch the steep grassy slope on the left which can be slippery. It 

would be advisable not to let students stray beyond the low cliff or approach the higher cliffs behind and at 

either side. 

For James Hutton, the crucial point was that the sandstone layers have been disrupted by intrusion of the 

magma that would eventually cool to form the dolerite. So the sandstone was here first, and enough time had 

passed for sand from the sea floor (as Hutton saw it) to be consolidated into solid sandstone. It was not 

simply a matter of different layers forming one upon the other under the sea; a more complicated explanation 

was required which needed a long time gap between different types of activity. We now know that there's an 

approximately 20 million year gap between the formation of the sedimentary rocks (early Carboniferous, 

around 340 million years ago) and the intrusion of magma that formed Salisbury Crags (around 320 million 

years ago). 

If you look to the left of the classic buckled sandstone layer in Figure 20 you can find the same layer appears 

again with another broken and twisted junction. So a portion of the sandstone bed has been wrenched out 

and carried away in the flow of magma. 

Return to the Radical Road and follow it uphill along the base of Salisbury Crags. 


Location 8: View of the Castle crag and tail NT 2679 7311 

There are usually good views of the Castle and the 

Royal Mile, sculpted by the ice sheet travelling from 

the west. Further south, Blackford and Braid Hills 

have the same shape with a steep scarp slope to the 

west and a long gentle eastern dip slope. 

Below the Radical Road an even scree slope has 

developed since the ice age as Salisbury Crags 

continues to crumble. 

The main road passes through the glacial scoop 

eroded into sedimentary rocks as the ice sheet 

squeezed past the Crags. The Grassmarket and 

Princes Street Gardens are similar features around 

the Castle Rock. 

Figure 21: View of Edinburgh Castle from the Radical Road 

Location 8 is the final stop in the suggested itinerary. From here you can complete a clockwise circuit back to 

the start point by either continuing along the Radical Road path or by returning to the Queen's Drive behind 

you and following the main road round the foot of the Salisbury Crags scree slopes. 

Acknowledgements 

This guide was written in 2009 as part of the Scottish Earth Science Education Forum's Earth Science 

Outdoors project. Funding for the project came from Scottish Natural Heritage and a Science Engagement 

Grant from the Scottish Government. The guide was written by a team of earth scientists and educators, and 

we are grateful to all the organisations and individuals who have been involved. Photographs are by Angus 

Miller unless stated otherwise. 

Lothian and 

Borders RIGS 

If you have used this guide, we would like to hear from you! We value all comments and suggestions for 

improvement, and even a quick email to let us know you've used the guide is useful to help demonstrate the 

interest and demand for guides like this – please contact us through the SESEF website. 

© 2009 Scottish Earth Science Education Forum. Permission is given to adapt and use this guide and 

images for educational purposes only. 


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