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Barrow Hill L.N.R., Dudley

KEY STAGE 2 TEACHING TRAIL
© GeoconservationUK ESO-S Project, 2014


It is anticipated that the ideas and materials presented here will be adapted by schools, and others, to be more appropriate for their own purposes and programmes of study.

In such circumstances please acknowledge the source as the Earth Science On-Site project.

Key Stage 2 Downloads
Activity Sheets (pdf file, 657 KB)
Teachers' Notes (pdf file, 685 KB)

Contents

Introduction

On the journey

On the journey to Barrow Hill pupils should be encouraged to look out for ways in which rocks and materials derived from them, including bricks tiles and concrete, are being used in the environment. If this topic has not been part of the preparation for the visit, it should be covered in the follow-up. A copy of The Dudley Volcano leaflet from Dudley Museum, Local Tourist Information Offices and St Mark’s Church would also be useful.

Items to bring on the Visit

Appropriate clothing and footwear. Wellies are easy to clean.

Enough copies of worksheets/notes etc. selected, or modified, from the list below:

  • Site 1a. Activity Sheet 1 - Map and Church Study.
  • Site 1b & 1c Activity sheet 2 - St Mark’s Church.
  • Activity sheet 3 - Rock Reference Sheet (alternative version).
  • Site 1d Activity Sheet 4 - 1st Churchyard Recording Sheet.
  • Site 1d Activity Sheet 5 - 2nd Churchyard Recording Sheet.
  • Site 2 Activity Sheet 6 - What will make my gravestone last?
  • Site 3 Activity Sheet 7 - Study Of St Mark’s Church Gate.
  • Site 4 Activity Sheet 8 - Study Of The War Memorial.
  • Site 5 & 6 Activity Sheet 9 - Study Of The Vicarage Wall.
  • Site 7 Activity Sheet 10 - Poolside Soil and Vegetation.
  • Site 8a Activity Sheet 11 - Barrow Hill Quarries.
  • Site 9 Activity sheet 12 - Barrow Hill Summit Viewpoint.

Plus: Clipboard, notebook, sketchbook, camera, magnifiers, water dropper bottles, laminated piece of mm graph paper, tape measure, compass and materials for any other fieldwork activities [eg relating to wildlife].

Teachers and adult helpers should each have dropper bottle with dilute acid for testing limestone and marble. Domestic lime de-scaler may be used, and should be diluted to adequately react with limestone/marble [try x 10 dilution]. A bottle of water and tissues.

Equipment for collecting soil samples.

On Arrival

Follow any guidance given by the church authorities at St Mark’s when arranging the visit, even if you are not visiting the churchyard. There is normally enough room to park a coach in the designated area by the church gate in Vicarage Lane [off A4101]. Notice the use of stone in the wall and gate, but this can be looked as part of the walk up to Barrow Hill, after visiting the churchyard.

There are toilets at St Mark’s. Liase with the church authorites to arrange opening. Remind the children of Health and Safety issues and the need for respectful behaviour in the churchyard, especially towards people visiting graves. On Barrow Hill avoid dog poo.

Using the pupil activity sheets

The Earth Science teaching trail and pupil activity sheets are very detailed, as there is a lot of information to be found in the rocks in both the churchyard and Barrow Hill. In the notes reference is also made to weathering, soils and wildlife. Teachers will need to decide which materials are appropriate for their pupils to use and adapt the sheets accordingly.

There are plenty of opportunities to record information by taking photographs, sketching, mapping and note-taking to aid follow-up work. When soil samples are taken the location should be marked on the map. With younger or less-able children it may be useful if the adult helper acts as a “scribe”, recording the agreed answers on a copy of the activity sheet. All should complete their own sheets as part of follow-up work, as an individual record of the work they did on the visit.


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Figure 1: Map of the Barrow Hill Sites

Earth Science On-Site Trail

The Trail is in three parts:

  1. St Mark’s Church (Site 1),
  2. The Churchyard and surroundings (Site 2),
  3. Barrow Hill and surrounds (Sites 3 to 9).

The teaching trail notes, which follow, incorporate the pupil activity sheets (See Activity Sheets (pdf file, 657KB) with teaching points, answers, interpretation and other comments. Copies of the completed sheets can be found in Teachers' Notes (pdf file, 685 KB).

At many points in this itinerary large groups of pupils may be divided into workgroups and dispersed, under supervision, between different locations to avoid crowding.

Schools local to the area may wish to visit St Mark’s churchyard and Barrow Hill on separate occasions.

Parking for smaller vehicles is possible just south of the church gate on Vicarage Lane. Remind the group of appropriate behaviour in and around a church, and then take the group through the church gate into the churchyard.

We are looking at a range of different rocks being used in the church, its construction and as monuments in the churchyard. You may wish to split the class into four groups to look at the four parts of the church: a) South side exterior, b) Roof, c) South door, and d) Inside.

Site 1. St Mark’s Church

Key points to investigate

1. To look at St Mark’s Church and the materials used in its construction, including man-made materials, and the crack in the south wall – a result of the Dudley earthquake of 22 September 2002, at 23.53 GMT [23 Sept 00.53 BST].

Site 1a. (Activity Sheet 1) – St Mark’s Church (south side)

Follow the path to the front of the church to look at the south side of the exterior.

Questions/Teaching points Answers/Interpretation/Comments
Begin by asking pupils to orientate themselves on the map on Activity Sheet 1.  
Describe the main material used for building the walls of the church. Buff coloured, rough feel, made of sand/grit grains, shows layering.

Corners are smoothed blocks, others have chiselled pattern.

Use 1mm graph paper to check the size of the grains: Mostly under 1mm, or mostly 1 – 2 mm, or mostly over 2 mm Mostly 1-2 mm.
Are the grains easy to break away or are they well-cemented together? Easy in places.
The grains are made of a hard mineral. What is it called? Quartz.
From your knowledge of rocks suggest a name for this rock type. Sandstone or gritstone [coarse sandstone].

It is Gornal Grit, deposited in the Silurian Period.

This type of rock is often porous, depending on how much cement is between the grains. Use your water dropper to test this. Slightly porous.
Use your dilute acid dropper to test the rock. Grains of quartz will not react, but does the cement holding the grains together? (Use water to wash any site that has been tested). No reaction. The cement is silica/quartz.
What does the layering in these blocks tell us about how they were formed?

[You might have done an experiment in school with water and sediments like sand and mud].

Layering like this tells us that the grains of sand/grit settled in water, forming layers. [Some blocks show cross-bedding, indicating deposition in flowing water.]
Most rocks found naturally in England are layered and made originally of soft sediments. What name is given to this major group of rocks? Sedimentary.
Look for evidence that the walls have suffered from weathering since the church was built in 1849. Sandstone shows blackening and parts may rub off or flake off.
You may have noticed the large crack in the wall. What might have caused it?

If you go into the church you might find that floor tiles have been loosened which line up with the crack outside.

Subsidence from old coal mining underneath is a possibility, as is movement along faults in the Earth.

23/24 September 2002 Dudley Earthquake caused movement here, which can be seen on the North side too, in the upper left set of windows.

Can you suggest what the small strips fixed across the crack are for?

Another one is on the bell tower.

They are strain gauges, used to check if the crack is getting wider.

Discuss the implications for the next 100 years!! There is a need to underpin the foundations with concrete to prevent the church falling down. Costs may be too great – demolition may be needed.

Site 1b. (Activity Sheet 2)

Move back far enough to see the upper and lower church roofs. Group leaders might usefully have pieces of roofing slate and tile to hand for closer inspection of the building materials.

Questions/Teaching points Answers/Interpretation/Comments
Describe the materials used to make the upper and lower parts of the church roof. The Upper roof is made of tiles.

The Lower roof over the aisles is of thin sheets of purple/grey material [slate].

Your teacher might have samples to look at and test for porosity. Tiles may be very slightly porous.

Other [slate] is not porous. Hard.

Name the rock type used on the lower roof. Slate.
This rock was originally a clay-rich rock [like mudstone or shale] but has since been heated and squeezed by great pressure.

What name is given to the major group of rocks that have been changed by heat and pressure?

Metamorphic.
What advantages does this rock type have for it to be used on roofs. Not porous. Can be split into thin sheets, making it light enough to be nailed onto the wooden slats. Thick slabs of rock would be too heavy and the roof might collapse.
What man-made materials are used on the upper roof? What are they made from? Tiles, made from thin slabs of soft clay, fired at high temperatures in a kiln to make them hard and virtually non-porous.


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Figure 2: Earthquake damage on the south wall
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Figure 3: The Church entrance

Site 1c.(Activity Sheet 2) Move towards the South door and look at the area in front of the door (see Figure 3).

Site 1c. The Church entrance

Questions/Teaching points Answers/Interpretation/Comments
What man-made materials are used in front of the door? Bricks and tiles.
What are they made from? Made from soft clay, shaped and fired at high temperatures in a kiln to make them hard and virtually non-porous.
Bricks and tiles sometimes have the name and place of the firm that made them. Look out for examples around the church and graveyard. 10m to the west [left] of the South door are bricks marked “J Collins, Pensnett”. The clay is likely to be Etruria Marl [Upper Carboniferous], possibly dug from a pit at Tansey Green to the NW of Barrow Hill.

What other man-made material can you see at the South door?

[You can find out how this is made later].

What is the step made from?

What has happened to the step over the years?

Sandstone – grey colour, 1-2mm.

Step has been hollowed by people walking on it [human erosion].

4. Site 1d. (Activity Sheet 2)

Take the group quietly into the church and look around. Remember, the focus is on human use of geological materials which have been selected because of their physical properties.

Questions/Teaching points Answers/Interpretation/Comments
Describe and identify what rock the pillars are made of. Fine grained [1mm], hard, red sandstone, showing layering. Likely to be Triassic in age. Bases of grey sandstone.
Describe and identify materials used in making the new floor of the church. Light creamy/grey coloured, with some layering. Possible sighting of fossil shells. Limestone. Use acid only on spare pieces which may be available on request. (Wash it with water afterwards).
Suggest why sandstone has not been used for the church floor. Wears away too easily when walked on [human erosion]. Notice how the step and floor of the porch has been worn.
Old floor tiles can still be seen and have been re-used in places.

Why are tiles commonly used for floors?

Tiles made from clay and glazes are harder-wearing and can be replaced easily and cheaply.

They can be decorative – these are Minton tiles, made in Stoke-on-Trent, and used across the world.

Look at the font and pulpit. What are they made of?

What are the small columns made of?

Why has this stone been chosen for the columns?

Well-cemented grey/cream sandstone 1-2mm grains, hard, not porous!!

Alabaster [gypsum, probably from Tutbury, East Staffs].

They are decorative and colourful.

Look out for signs of cracks from the Dudley earthquake of September 2002. Tiles were lifted across the sanctuary. They are still loose!!

Site 2. The Churchyard Survey

On the preliminary visit the teacher will be able to select for this exercise suitable rows of ten headstones showing a variety of rock types, of differing ages and states of weathering (see Figures 4 & 5). Supervised groups can then work in different parts of the churchyard. Remind the children what they are investigating and that their results will be combined back in school (see BAR6 KS2 Prep).


The groups of children will need: clipboard; Activity Sheet and Rock Reference Sheet [Two versions are available at different levels. See Activity Sheets (pdf file, 657KB)]. Group leader should hold water and dilute acid droppers and tissues to wipe off any acid used in tests as requested.


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Figure 4 and 5: Examples of monuments in the churchyard


Key points to investigate
  1. to identify different rock types and look for evidence to indicate how they were formed, based partly on the preparatory work;
  2. to see if there have been any changes in the use of rock types as memorials over time and suggest reasons.
  3. to look for evidence of weathering of the rocks since they were put in place [usually within a year of the date of the first named death].
  4. to look for man-made [modified] materials being used, including brick [glazed white or black or unglazed], and cast ceramic monuments. These materials were originally clays, which have been fired in kilns to make them hard and durable. Think of man-made metamorphism! Concrete, a human made “stone” is occasionally used for surrounds.

Site 2. (Activity Sheets 4 and 5) The Churchyard Survey.

Instructions to groups
  • Use the Rock Reference Sheet below, or the one on Activity Sheet 3 to help you to identify the rocks used in your row of headstones. Not all those in the Reference *Sheet will be in your row. Ask your teacher to use a water dropper to test for porosity and test with dilute acid on the back to see if it fizzes. Wash and wipe off with a tissue.
  • Record the date of death of the first person buried in each grave.
  • Check if the gravestone shows any signs of weathering and record if it is beneath trees or has moss or lichen growing on it, or is polished.

Rock Reference Sheet v1 (see Activity Sheet 3 for a shorter version)

Rock description & formation Type, Group, & other details
I am made of grains of sand, they are mostly bits of a glassy mineral called quartz stuck together with quartz cement, which makes me quite hard.

I can be quite soft. I can vary in colour – grey/cream/red. Sometimes I am layered on my top or sides and I was formed in water.

Rock type: sandstone.

Rock group: sedimentary.

Sometimes I am porous.

I do not fizz with acid.

If I am soft my grains easily wear away.

I am made of large pink or whitish crystals called feldspar. My glassy or grey crystals are quartz, and my black crystals are mica. My minerals interlock because they crystallised together from molten magma. They feel smooth when they have been polished. Larger crystals indicate slower cooling at greater depth in the Earth’s crust. Rock type: granite.

Rock group: igneous.

I am not porous.

I do not fizz with acid.

If I am not polished and have been here a long time I might have plants growing on me.

I am made of small crystals locked together.

My crystals are white and sugary.

I am made of the mineral called calcite.

I was once a limestone, but have since been buried and heated at great depth in the Earth’s crust causing me to re-crystallise.

Rock type: marble.

Rock group: metamorphic.

I fizz when acid is put on me and I suffer weathering from acid rain.

If I have been here a long time I might be blackened with plants growing on me.

I am made of bands of pink or white crystals interlocked together, called feldspar.

My darker bands are made of hornblende.

I was originally mud, but have since been buried, heated and squashed at great depth in the Earth’s crust. I am very hard and feel rough, unless I have been polished.

Rock type: gneiss [sounds like: “nice”].

Rock group: metamorphic.

I am not quarried from this area.

I am not porous.

I do not fizz with acid.

I am a recent arrival.

I am made of black or dark green crystals and a sparking white mineral called feldspar.

My minerals interlock because they crystallised together from molten magma.

Larger crystals indicate slower cooling at greater depth in the Earth’s crust.

I am very hard and feel rough, unless I have been polished.

Rock type: gabbro [large crystals].

dolerite [smaller crystals].
basalt [microscopic crystals].

Rock group: igneous.

I am not porous.

I do not fizz with acid.

Stone masons often call me “black granite”.

I am made of bits of shell fossils with lime mud and the mineral calcite sticking them together, and I can vary in colour – grey/cream/white. I fizz when acid is put on.

You may be able to see layering on my top or sides. I was formed in layers under water.

Rock type: limestone.

Rock group: sedimentary.

I may have been quarried nearby.

Sometimes I am porous.

I fizz when acid is put on me.

I suffer weathering from acid rain.

I am made of microscopic minerals.

I may be grey, purple or green in colour.

I am quite hard and can often be split into thin sheets.

I was originally mud.

Rock type: slate.

Rock group: metamorphic.

I am not porous.

I do not fizz with acid.

I am not really a rock. I was originally soft wet clay, but have been moulded into shapes and fired in a kiln to make me hard.

Sometimes I am dipped in a glaze and fired again. This makes me shiny.

I may be brick or tile. If I am not glazed I might show signs of freeze-thaw weathering, with pieces flaking off. I may be shaped to form a headstone. Such ceramic gravestones are not common.

I am made from local clay.

Preliminary results of the churchyard survey can be discussed (see below) with the class on-site, and followed-up with figures collated back in class. The survey results should help the group to answer the questions in the follow up exercise in KS2 Preparation.

Site 2. (Activity Sheet 6) What will make my gravestone last?

The Earth Science On-Site Follow-Up discussion should focus on pupils trying to understand how weathering and rock type combine to make more, or less, resistant headstones. Ask the group to work out what kind of stone would make the longest lasting headstone?

Questions/Teaching points Answers/Interpretation/Comments
Why do the polished rocks show little or no sign of weathering? They are new! Rain runs off & quickly dries. Lichen and moss have nothing to help them to take hold. i.e. length of time exposed to weathering is important.
What happens to marble and limestone? They weather easily, by acid in rainwater reacting with the mineral calcite and dissolving it. i.e. rock type is important.
What happens to porous sandstones? They weather easily, as they have weak cement holding the grains together.

Rain and wind may knock off grains. In winter the rock freezes and thaws, breaking away grains or even splitting the slab from the top. i.e. water getting inside the stone is important.

Why do the old sandstones look dirty? Dirty atmosphere in the past, with sooty smoke. Clean Air Acts of 1950s i.e. pollution is important.
Rough hard rocks like granite and the old sandstone often have lichen growing on them. Suggest a reason why. The rough surfaces can hold some moisture and give lichen a foothold. i.e. draining water from the stone is important. (Lichen also grow on roughened marble. Lichen thrive in clean air.)
What effect do overhanging trees and shrubs have on the gravestones beneath them? They tend to make them darker and damper, enabling mosses to take hold, especially on rough surfaces. i.e. shade and remaining wet is important.
The main direction of the wind and rain is from the southwest. Has this affected the weathering of gravestones? Marble, limestone and porous sandstones may be more weathered on the S/W side. i.e. aspect (direction of facing) is important.
Which rock type would you choose for a gravestone and why? Polished granite, gabbro, or gneiss!

Least affected by weathering – will last!!

The investigation of uses of natural and man made materials in the built environment continues at the next four sites.

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Figure 6: Site 3. St Mark’s Church Gate

There is a marked contrast between the neatly cut sandstone used for the church gate and the rough, cheap recycled materials used higher up Vicarage Lane, on the way to Barrow Hill Quarry. The dressed sandstone is quite coarse grained. It is Silurian in age, known as Gornal Grit, from old quarries 3 km to the north, but now closed. A great variety of rough, irregular shaped lumps of sandstone, dolerite and furnace slag have been used in the vicarage wall to the north. The war memorial, on the other hand, is totally different, made of a sandy limestone containing fossil shells.

Site 3. (Activity Sheet 7) St Mark’s Church Gate

Look closely at the materials used to build the church gate and wall (see Figure 6).

Questions/Teaching points Answers/Interpretation/Comments
First mark Site 3 on the map on Activity Sheet 1. Label it “Site 3”.  
Describe the shape of most of the stones used in the gate and wall. Rectangular, cut to regular shape.
Describe the rock used. Creamy colour, rather dirty/weathered, layered, made of 1-2mm sand grains stuck together.
What rock type is it? Sandstone.
What can you say about the layering in each block?

You might have done an experiment where sand settled out in a container of water.

Flat bedding/layering indicates that the sand settled in quiet water.

The cross-bedding indicates settling in moving water. Need to prompt!!

What evidence can you find to show that weathering has taken place? Sand grains rub off, uneven wear, dirty colouring. One block to left is badly weathered – likely a different sandstone!
Look at the roof of the gate and suggest why the roofing materials were chosen. Roof is also made of the same type of sandstone blocks, cut to shape, with carvings. In keeping with the style of the rest of the structure!
What do you think the barrier is made from? Suggest why it needs painting. Gate made of iron [likely wrought, rather than cast]. Painting to prevent rusting!

Site 4. (Activity Sheet 8) The War Memorial

Walk the group down to the corner of Vicarage Lane to the war memorial (see Figure 7). Warn the group to be careful of traffic. Look closely at the materials used to build the war memorial and the nearby wall. What materials are they and where were they obtained from?

Questions/Teaching points Answers/Interpretation/Comments
First mark Site 4 on the map on Activity Sheet 1. Label it “Site 4”.  
Describe the rock used to build the war memorial and its base. Dirty creamy coloured 1-2mm grains which look sandy, but react with acid, contains fossil shell material.
What rock type is it? Limestone [strictly a sandy limestone with fossil shells] a sedimentary rock.
What clues tell us that this rock formed in the sea? Fossils of sea shells – brachiopods.

Shows layering.

What evidence can you find to show that weathering has taken place in the 80+ years it has stood here? Blackened, bits rub off. Also chemically weathered by acid rain - harder fossil fragments stand out from parts removed.
Using Activity Sheet 8 ask the group to look around the memorial site and see how many other geological resources have been used to make the memorial site. The limestone for the memorial itself, plus the metal plaque (obtained from ores), the bricks (obtained by firing clay), cement (obtained from limestone etc.) and the tarmac (obtained from petroleum) and rock fragments to surface the pavement, as well as the soil (weathered from the rock below).


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Figure 7: The War Memorial


Move the group back past the church to the north up the Vicarage Lane hill to Site 5 (see Figure 8). Look closely at the materials used to build the vicarage wall.


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Figure 8: Site 5. The Vicarage wall

Site 5. (Activity Sheet 9) The Vicarage wall

Questions/Teaching points Answers/Interpretation/Comments
First mark Site 5 on the map on Activity Sheet 1. Label it “Site 5”.  
Describe the shape and size of most of the materials used to build the wall here. Irregular, 10 – 20 cm, uneven, rough, need plenty of mortar.
Find a rock made of grains of sand. What is its colour and rock type? Creamy / pale.

Sandstone.

Find a hard rock made of small crystals. You may see smaller bits all over the place. What is its colour and rock type? Dark/black.

Dolerite.

Find a hard glassy material that is not a natural rock.

It is waste slag from an iron furnace.

What else can you see in it?

Full of holes/bubbles.
Why do you think these materials were used in the wall here, away from the church? Using waste or recycled materials reduces the cost of building. There was no need to use expensive dressed stone beyond the church.


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Figure 9: Site 6. The Upper Wall

Site 6. (Activity Sheet 9) The Upper Wall

Take the group through the stile and inspect the continuation of the wall on the left (see Figure 9).

Questions/Teaching points Answers/Interpretation/Comments
First mark Site 6 on the map on Activity Sheet 1. Label it “Site 6”.  
Describe the materials used to build this wall. Irregular shapes, 10-20cm, glassy with holes/bubbles. No clear sign of mortar holding it together [chunks have fallen out].
This hard glassy material is not a natural rock, it is waste from an iron furnace. What is it called? Slag.
Which wall is older – this one, or the one by the church? Why do think this? This upper one. Tumbled down, more overgrown. This was probably a pre-turnpike coaching road, built before the church and this is the original wall.
Why do you think these materials were used for this wall? Locally available from iron furnaces – recycling waste!
Keep a look out for materials along the path. Note any others that you find. Pieces of brick, ironstone and limestone [used in iron furnaces].

The whole hill has been used as a dumping ground for centuries.


Continue north along Vicarage Lane which becomes an unfenced path with steps. Look out for waste materials along the path and in the wall. The rocks of the Barrow Hill area have been dug over for centuries!

Go over the hill, taking great care descending the steps. You are now well into Barrow Hill Local Nature Reserve. There is great potential to use a variety of teaching materials to investigate ecological topics, related to the woodland here and the grassland beyond.

Forty metres beyond the steps is a fork in the path. To the right, the path leads to two small quarries in the dolerite (Site 8).

Here it might be convenient to split a large class into two groups. The dolerite quarries are quite small and teachers may wish to take one group to Poolside (Site 7) to glimpse the red muddy rocks into which the dolerite was intruded, whilst the other group views the dolerite at Site 8. The groups could then swap over.

To reach Poolside, continue NNW along the path down and across the meadow to Poolside (see Figure 1). You will soon realise that you are onto soil weathered from red muddy rocks, called Etruria Marl. You have crossed a fault, which runs east-west on the north side of Barrow Hill. [See the Barrow Hill Trail Guide].

Site 7. (Activity Sheet 10) Poolside

Key points to investigate

We are looking at four aspects of these exposures of rock:

  1. to find out what happened to the rocks after they were formed;
  2. to find out what is naturally happening to them today or in the recent past;
  3. to find out what they have been used for by Man.

Along the side of the path and around Poolside you might have noticed changes on the ground.

Questions/Teaching points Answers/Interpretation/Comments
First mark Site 7 on the map on Activity Sheet 1. Label it “Site 7”.  
Try to explain why the soil here is wet,

You might have looked at soils in school.

It has been rained on!

Clay holds moisture – dry clay is porous, it absorbs water and swells to fill the pores, so wet clay is not porous.

Why is there a pool here on this material? Water does not soak away through clay and this is a low point in the field.
There were several clay pits in the area, like Tansey Green, to the west. This clayey sedimentary rock is known as Etruria Marl.

What was this clay used to make?

Bricks and tiles [some seen around the churchyard & in local area]. See follow-up notes in Preparation & Follow-up.

NOTE: the red clay is rapidly weathered from red mudstone. The mudstone needs to be dug up and piled into heaps to weather for several weeks before being used to make bricks. Sun, rain, wind and frost help to break it up.

Check with your teacher if a soil sample is to be taken here. This soil will be a clear contrast with any taken from top of Barrow Hill which contains fragments of dolerite.
What plants can you identify here, most of which thrive in wet conditions? Moss, rushes, buttercups etc.
Tell the group that this marl was deposited on an ancient river floodplain, 300 million years ago, quite close to a volcano, and they are going to see what is left of the volcano.

Site 8. (Activity Sheet 11) Barrow Hill Quarries

Site 8a. Barrow Hill Quarries (The Barrow Hill Volcano)

From Poolside, return SSE along the same path to the fork in the path [mentioned above], 40 metres north of the steps and turn sharp left. Twenty metres from the fork are Barrow Hill Quarries. To your left is North Quarry (8a), to the right is South Quarry (8b).

Go left into North Quarry. Keep to the path and encourage the children to look around and report what they observe.

Teacher will need a hammer [& goggles] to break a lump of dolerite to give a fresh piece for close inspection. You will also need a magnifier, small piece of 1mm graph paper, dropper bottle of water, dropper bottle of dilute acid.


Questions/Teaching points Answers/Interpretation/Comments
First mark Site 8 on the map on Activity Sheet 1. Label it “Site 8”.  
What clues have you found that tells us this was once a quarry? Steep/vertical rock faces. Flat floor. Not a natural valley, no river.
Ask the group to pick up and describe a piece of this dark rock.

Look for a fresh piece to see if it is layered and made of grains cemented together, or made of crystals locked together.

Irregular shape.

Black colour.

Not layered.

Made of small crystals locked together, and therefore is NOT SEDIMENTARY.

Check the size of the crystals with a magnifier and graph paper scale:

about 1mm, over 1mm, under 1mm.

About 1mm.
Is the rock porous or not? Not porous.
Does the rock react with acid? No.
Check the Rock Reference Sheet to see what rock type we have found here. Dolerite, an igneous rock which forms underground.
To which major rock group does it belong? Igneous.


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Figure 10: Site 8a. Jointed dolerite
BAR7KS2f11.jpg
Figure 11: Hexagonal columns

Site 8a. Jointed dolerite

Questions/Teaching points Answers/Interpretation/Comments
What you can see in the quarry face on the left? Dark rock, many vertical cracks running right through from top to bottom. (These are the edges of (more or less) hexagonal columns. See Figures 10 and 11.)
The cracks are called joints and they often look like columns.

Suggest a reason why igneous rocks often show cracks [joints].

Molten rock [magma] shrinks and cracks when it cools [at right angles to the cold rocks above and below]. They often form (roughly) hexagonal columns.
You may have seen pictures of the Giant’s Causeway [Antrim], or Fingal’s Cave [Staffa], made of similar rock to Barrow Hill. How else are they similar? Similar joint/cracks producing hexagonal blocks of rock.

Check to see if there are any 6 [or 5 or 7] sided blocks here on the ground.

What is happening to the broken rock that has fallen from the face to form a scree slope? It is being weathered, with plants growing among the rocks (NB brambles!) and soil is forming.
What signs of weathering can you see in your piece of rock? Some change of colour on outside, tends to go brown as a result of oxidation of the iron-rich minerals.

In extreme cases of weathering the edges and corners of a rectangular block can weather away leaving almost a sphere!

Turn the group around to face the opposite face. Point out the red rock embedded in the dolerite at the top of the scree. Tell the group it is a piece of red marl (as seen at Poolside). Ask then what they think happened to the marl when the molten magma surrounded it? It would have been baked at a temperature of around 800 to 1000°C.

NOTE: The scree is steep and loose. It is not advisable to climb on it.

What would have happened to any water trapped in the red Marl? It would have turned to steam, making the whole episode very explosive.
Ask the group what all this magma and explosive activity might have caused at the Earth’s surface (300 million years ago)? A volcano.

Site 8b. Barrow Hill South Quarry

Return the 10 metres to the fork in the path, then left into South Quarry if you want to collect a soil sample. The scree here is mainly small angular pieces of dolerite, probably washed down slope by the rain, mixed with some soil.

Site 9. (Activity Sheet 12) Barrow Hill viewpoint

Return to path, up the steps and over the top to the path on the left, leading to the summit of Barrow Hill [a metal cross marks the spot]. Remind the group that the dolerite rocks in the quarry below were formed underneath a volcano millions of years ago.

The summit is an excellent viewpoint to review the main themes of the visit and by referring to features of the landscape and the use of geological resources. The map in the Barrow Hill leaflet, available from Dudley Museum, Local Tourist Information Offices and St Mark’s Church is essential here, with the skyline profile to help locate distant features. It would be useful to collect a soil sample containing a few chippings of dolerite.


Questions/Teaching points Answers/Interpretation/Comments
First mark Site 9 on the map on Activity Sheet 1. Label it “Site 9”.  
This igneous rock once fed molten rock to a volcano. Ask the group where they think the volcano is now? The volcano has been weathered away many millions of years ago. It used to be about 1Km above where you are now standing. But this and the surrounding thickness of rock have been completely weathered and eroded away leaving the present landscape (see Activity sheet 12).
Using the museum leaflet identify some of the hills on the skyline. Ask why they have not been worn away as much as the rocks below the lower ground? These rocks are more resistant to weathering and form hills – as does the dolerite at Barrow Hill.
Ask the group why the dolerite was dug from the Barrow Hill quarries below them. It is a hard rock (and used for road stone). As they have seen it wasn’t very good for building walls!
Point out the housing estate and hospital to the south east. Ask what materials have been used to build it that have not come from the ground? Almost nothing!!

Brick, cement, metal, plastic, plaster, tarmac, glass all come from earth materials. Even the soil is weathered from rocks.

Natural fabrics (like cotton or wool) are the most likely answers, but cotton grows in soil and sheep grow fleece by eating grass – that grows in soil and was weathered from rocks!

Take the group down the hill to Vicarage Lane and back to the car park.

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