1. Mini Geo-Trail
2. Geo-Trail Map
3. Directions
4. Bibliography

Mini Geo-Trail

In the following route description, notes concerned with navigation are show in plum, descriptions of features able to be seen are in black and warnings are given in red.

Please Note: a more detailed description is available in CIAS newsletter No. 100, Feb., 2011 from which this geo-trail is abridged.

Looking west through Loftus Quarries. The quarry floor is Alum Shale, and with Cattersty Cliff in the background.

Geo-Trail Map

Please note that a downloadable annotated version of this map will be made available soon.

Click here to see the Loftus Quarries Geo-Trail Map.
NB: Numbers on map correspond with numbered items in text.

Directions

Please note that numbers shown in black refer to the numbers given on the map.

View east from the car park at Skinningrove showing Hummeresa Cliff which carries the Cleveland Way to Loftus Alum Quarries.

• Car Park: At NZ 713 201 by the mouth of Skinningrove Beck north of the village.
• Make your way across the beck and follow the Cleveland Way up the steep, stepped path and then eastwards where there is a view of the Old Gut dock (marked 1 on the plan). Pass the path down to the shore at NZ 725 198 and North Warren Cottage (Tile Sheds). (2 cisterns (2) are missed unless one deviates along the coastal path). At NZ 735 197 fork left off the Cleveland Way to go down the track in to the quarries.
• 3. Where the coastal path rejoins the track Loftus Quarries come in to view. There is a sandstone quarry (4) and below it a large alum shale quarry (5), its south-eastern face being the location of the murchisonae beds.
• Continue down the track.
• 6. (NZ 737 200) – Foot of ramp track. There are views of tiered quarries to the NW. There were two sets of steeping pits and the cliff edge (7) where there is now a crown hole, the result of jet working. To the east one can leave the path temporarily to examine the alum shale face close by.
• Cross the embankment and follow the path for about 200m to, just before a large fallen block of sandstone, descend down a faint path to the site of the smithy (8).
• 8. (NZ 739 201) – This is the site of the smithy and 2 steeping pits as shown on the 1st edition O.S. map. Little is seen but there are indications of other steeping pits on the cliff edge to the west.
• Go down the short ramp into the ‘kidney’ quarry immediately to the east.
• 9. (NZ 740 201) – ’Kidney quarry’. This quarry is sheltered from the north by an in-situ shale wall that has an opening for waste disposal over the cliff. The O.S. map shows that there was a set of 6 steeping pits here.
• Trek eastwards over the desolate landscape, crossing several cols and quarries (scoops) and passing archaeological locations (10), (11) and (12).


The desolate-looking quarry floor which occurs within Loftus Quarries.

• There is the opportunity to look for; (a) Zone ammonites such as species of Harpoceras and Dactylioceras and (b) the small bivalve Dacryomya ovum regarded by Hunton as characteristic of shale suited to alum making (but these are unlikely to be found; researchers believe that this was the time of slow recovery from an major sea floor extinction event (during formation of the Jet Rock).
• 13. (NZ 744 200) – There is a stone slab platform here, probably the base of a steeping pit, slightly bowed as a result of expansion of the shale beneath it. It is a good spot to view the archaeological remains (14, steeping pits, cistern and lengths of a stone trough) in the quarry further to the east and examine large limestone concretions with Dactylioceras that are close by. The extreme eastern end of Loftus Quarries is not far beyond. Here, the Horse Back (15) is the landslipped ground between Loftus and Boulby Quarries.
• Make your way on a thin path to (16) (NZ 744 199) where a path goes up a steep but safe slope to the Cleveland Way.


View of the back-wall from the east end of the quarries close to the Cleveland Way.

• 17. (NZ 743 199) – This is the site of a reservoir for the alum works, long and narrow in outline.
• Return westwards to Skinningrove along the Cleveland Way. There are at first fine views of the quarries to the north and the rolling dip slope to the south.

Disclaimer: Tees Valley RIGS Group cannot be responsible for the safety of anyone visiting the Loftus site whilst following this geo-trail. The accompanying map was accurate when this trail was devised in 2011, but these cliffs are prone to landslip through natural processes and paths may be lost.

Warning!
Due to the presence of unfenced cliffs we strongly suggest you take extreme care. The area is unsuitable for unsupervised children and all dogs should be kept on a lead. Please use suitable safety equipment when necessary. These cliffs are extremely dangerous and must not, under any circumstances, be climbed.

Taken from the eastern end of the quarries, this image shows the scale of the undertaking here.

Bibliography

See Loftus Quarry Site Description »»

©2011 Tees Valley RIGS Group.

1. Site Description
2. Geology
3. Access
4. General Assessment:
5. Associated Sites
6. Safety Information
7. Supplementary Information
8. Geology
9. Industrial History and Archaeology
10. Literature References
11. Mini Geo-trail
12. Surveyors

Site Description

Grid Reference: NZ 736 200 to 744 200
BGS Sheet: 34
OS Sheet: 94
Forwarded as RIGS: 30/09/2003

Site Status: SSSI (Not RIGS, other reference No. 53). Open access (National Trust).

Description of Geodiversity: Extensive former alum quarries of great historical and industrial archaeological interest. The Cleveland Way passes around the southern edge, along the top of the quarry back wall that is nearly 200m O.D. The coastal scenery is impressive.

Looking west through Loftus Quarries from near the Cleveland Way.

Geology

With shallow dips, the Jurassic strata that can be examined directly in situ are limited to beds near to the top of the Redcar Mudstone Formation. Higher beds in the cliff faces can be viewed and examined as fallen blocks.

• Saltwick Formation: This forms the southern back wall of the quarry, some 750m in length and over 30m in height. It is formed predominantly of river channel sandstones. It is difficult to reach and is best examined closely from fallen blocks.
• Dogger Formation: This is about 4m thick and is unique re. coastal exposures. It consists mainly of murchisonae shale and is one reason for the location being SSSI. The apparent transitional beds upwards to Saltwick Formation flood plain deposits are an important source of fossil plants.
• Whitby Mudstone Formation: There are extensive exposures of the lower beds that form the quarry floor (including some Mulgrave Shale).
• Reason for SSSI Status: (1) Occurrence of murchisonae shale, (2) Finding of various reptilian species. (Note: the SSSI status is named as Boulby but the site plan includes both Boulby and Loftus. The murchisonae shale only occurs at Loftus and the pterosaur is also from there. However, the other reptiles may have come from Boulby.)

View from within Loftus Quarries looking west toward Cattersty.

Geomorphology: Several past and potential landslips and rockfalls can be seen and, in contrast, examples of slow, gradual subaerial cliff erosion.

Historical geology: Lewis Hunton’s family were alum makers and estate agents here. Hunton’s study of the stratigraphy at Boulby Quarry, immediately to the east, was a major contribution to the development of geological science.

Industrial Archaeology:

• The quarry is a major alum site with several stages of development. However, industrial archaeological remains are somewhat sparse especially in comparison with Boulby.
• The quarries are underlain by the extensive underground workings of the Main Seam (Cleveland Ironstone Formation) of Loftus Mine that are exposed along the sea cliffs. Jet workings are also present along the sea cliffs not far below the lowest alum levels.

Access

The main access point is at NZ 735 198 where a track into the quarries branches off the Cleveland Way. This point can be reached on foot in various ways but particularly by following the Cleveland Way eastwards from Skinningrove where there is parking (see the mini-geotrail).

Access map for Loftus Quarries showing suggested parking in Skinningrove, extent of Boulby SSSI and North York Moors National Park.
(Click on map to enlage)

General Assessment:

The quarries are an excellent venue for demonstrating Lower and Middle Jurassic geology and industrial archaeology (alum workings).

Associated Sites

Boulby Alum Quarries (SSSI, other reference no. 54);
Hummersea sea cliffs and foreshore (Heritage Coast, other reference no. 51);
Boulby and Cowbar Nab Cliffs ((RC5, other reference no. 80);

Safety Information

PLEASE NOTE: Due to the presence of high unfenced cliff faces we suggest that this site is not suitable for visits by unsupervised children. Please remain well away from the cliff edge and ensure any dogs are kept on a lead. Because of their unstable nature these cliffs must not, under any circumstances, be climbed.

Disclaimer: Tees Valley RIGS Group cannot be responsible for the safety of anyone visiting this coastal site. The accompanying map was accurate when this trail was devised in 2011, but these cliffs are prone to landslip through natural processes and paths may be lost.

A NOTE ON FOSSILS

Please feel free to collect loose fossil specimens weathered from their places of original deposition. However, to enable future scientific study, and for the enjoyment of others who may follow in your footsteps, in situ fossils (i.e. those still embedded in their position of original deposition) should not be collected, but their positions noted and details passed on to TVRIGS, a local museum or other similar body.

Please follow the Countryside Code. Do not light fires. Take any litter home.

Supplementary Information

Geology

Structure: The succession is shown in the accompany section. The beds dip about 3° to the south.

Section through Loftus Quarries showing the general dip of the beds to the south.

Saltwick Formation (deltaic/alluvial): This forms the impressive back wall of the quarry and consists principally of massive lenses of river channel sandstone. It is generally difficult to reach owing to the fallen rock. Blocks, some extremely large, can be readily examined showing sedimentary structures such as cross-bedding and the imprints of plant remains.

Dogger Formation (marine incursion): The peculiar nature of this Formation at this locality was, perhaps, first noticed by Hunton (1836) who reported 10ft (3m) of shale at the top of the succession distinct from the Alum Shale. Later, Tate and Blake (1876, page 26) and Barrow (1888, page 43) described the section in some detail. Tate and Blake provide a lengthy fossil list of 20 species from bed 11, a 3 inch (7.5cm) thick bed described as ‘impure limestone dogger’ and reported Ludwigia murchisonae (an Aalenian zone ammonite) from bed 10 (‘shale’, 1 ft 6 ins (46 cm)) that is directly above.

The geology was subsequently investigated by Black (1929 and 1934) and has been summarised by Rastall and Hemingway (1940). Black’s section is also shown in the British Regional Geology, East Yorkshire and Lincolnshire (1948, page 38). Black records about 11ft (3.3m) of murchisonae beds with a basal ‘pebble bed’ (mainly of mudstone) overlain by ferruginous shale with bands of siderite mudstone nodules, some of which are fossiliferous with the basal bed carrying the zone fossil. The beds are overlain, apparently without any break, by flood plain deposits ascribed to the Saltwick Formation and including coaly shale and fossil plant beds. They are also cut out laterally by channel sandstone that passes laterally into a thin bed of sandstone above the plant-rich layers.

The locality is described by Tate and Blake as “…due north of Upton…”, i.e. at the extreme western end of the quarries at NZ 737 198, but is now rather difficult to reach and is in a poor state.

No comparable localities are known along the coast but similar beds are found inland especially at Cold Moor where they overlie the limestone-rich facies type that is also of murchisonae age. This implies that at Loftus Quarries there is a considerable gap in the stratigraphic succession with several missing time zones at the level of the pebble bed.

Alum Shale and Mulgrave Shale Members (marine, recovering from the anoxic event of the Jet rock): Some 30m of beds are exposed at various sub-quarry levels along the northern, seawards side. They probably belong to the Hard Shale sub-unit of the Member and beds below, the Bituminous Shale sub-unit of the Mulgrave Shale. They consist of weathered, friable, grey, iron-stained, poorly bedded, flaky shale with vertically disposed, small-scale jointing. Fossils, chiefly poorly preserved belemnites, are uncommon but, when seen, may be present in clusters. Small acicular crystals of iron-stained gypsum are common.

Occasional beds of lighter grey, calcareous, sometimes septarian, nodules are common and in places the bare shale surface is littered by loose pieces of these nodules. However, so far, Howarth’s (1962) detailed lithostratigraphic succession has not been elucidated. It is likely that the beds exposed belong to the lower part of the Member (the Hard Shale sub-unit) and to the upper part of the Mulgrave Shale Member.

The upper sequence of the Alum Shale Member is mostly obscured by waste dumps and rock falls but can be seen from a distance in some places. Black (ibid) and Rastall and Hemingway (ibid) report shale with cementstone nodules (and typical Alum Shale ammonites) overlain by about 2 feet (0.6m) mainly consisting of ‘chocolate mudstone’, of ‘doubtful age’, below the Dogger Formation pebble bed.

View Looking west from the eastern end of the quarries showing faces of Alum Shale.

Fossil reptiles: The SSSI description refers to type specimens of two plesiosaurs (Eretmosaurus maccroptera and Thaumatosaurus zetlandicus), one ichthyosaur (Ichthyosaurus crassimonus) and one pterosaur (Parapsicephalus (Schaphognathus) purdoni). The pterosaur was found at Lofthouse (Loftus) by the Rev. D. W. Purdon in 1881 and was described by Newton (Phil. Trans. Royal Soc. London, 1888). It is now at the British Geol. Survey, Keyworth (information from the Pterosaur data base where there are photos).

Geomorphology: The back wall of the quarry has been subject to rock falls and there is now much debris at its foot. At the top, on the Cleveland Way there are open fissures with the quarry wall being in a poor state.

At quarry level on the seawards edge there have been several landslips but also stretches of cliff where there has been little erosion since the publication of the first Ordnance Survey maps. The ground between the Boulby and Loftus Quarries illustrates how the original cliffs looked.

Historical geology: As noted above, Hunton (1836) published an important paper concerning the collection of fossils in-situ and their stratigraphic significance. Hunton’s home was at Hummersea House and he must also have been familiar with Loftus Quarries although his section refers to Rockcliff, Boulby where there was, at the time, an easy track down to the beach.

Industrial History and Archaeology

Alum: The alum works was started in the mid-17^th century and closed in about 1860. There was a major redevelopment about 1800 when a new alum house was constructed by Hummersea beach. The history and industrial archaeology of the alum works has received much attention in recent years and, in particular, there is the major survey by English Heritage (Hunt et al. 2004). The main sites are included in the mini-geotrail.

Ironstone: The Main Seam of the Cleveland Ironstone Formation has been worked extensively under the quarries as part of Loftus Ironstone Mine, the surface works of which are now the Cleveland Ironstone Mining Museum at Skinningrove (at NZ 712 193). The seams typically consisted of a Bottom Block (1.2m) and Top Block (1.5m) separated by a dogger or shale parting up to 0.2 m (but thicknesses varied across the reserve). Tuffs (1996) gives a brief and Chapman (1998) a detailed description.

Literature References

Maps

Geological Survey Yorkshire Sheet IX SW, scale 6 inches to 1 mile, 1878 (Ordnance Survey 1856).
his shows a large number of industrial features that have since disappeared such as several sets of steeping pits and an outline plan of the alum house.

Excursion Guides

Goldring, D. 2001. Along the Scar. Peter Tuffs, Guisborough, 145p. See pages 59-65.

Goldring, D. 2010. Guided Walk to Loftus Alum Quarries 24th July, 2010. CIAS Newsletter No. 100. See pages 5-11.
The mini-geotrail is based on this.

Geology

Barrow, G. 1888. The Geology of North Cleveland. Mem. Geol. Survey, H.M.S.O., London, 101p.
Pages. 9 and 12 show the Redcar Mudstone and Staithes Sandstone Formation sequences. The Main Seam ironstone section at the Old Gut is on page 19.

Black, M. 1929. Drifted plant beds of the Upper Estuarine Series of Yorkshire. Quart. Journ. Geol. Soc. 85.

Black, M. 1934. Sedimentation of the Aalenian rocks of Yorkshire. Proc. Yorks. Geol. Soc., 22, 265-279.
Details of the Dogger Formation succession

Goldring, D. 2011. Geological background to the North Yorkshire alum industry.
Paper in preparation.

Fox-Strangways, C. 1892. The Jurassic Rocks of Britain, Volume I Yorkshire. Geol. Survey, H.M.S.O., London, 551p.
Similar to Barrow, 1888.

Howarth, M. K. 1962. The Jet Rock Series and the Alum Shale Series of the Yorkshire coast. Proc. Yorks. Geol. Soc., 33, 381-418.
The main bed by bed description of the strata, followed by subsequent researchers.

Rastall, R. H. & Hemingway, J. E. 1940. The Yorkshire Dogger, 1. The Coastal Region. Geol. Mag., 77, 177-197 & 257-275.
This is the main detailed description of the Dogger Formation for the Cleveland coast. Pages 192 and 193 refer to the Loftus section.

Tate, R. and Blake, J. F. 1876. The Yorkshire Lias. John Van Voorst, London, 475p.
he measured section and fossil list of the Dogger Formation is on page 26 (cliff due north of Upton hamlet). Pages 132 and 133 show the ironstone section as seen on the path to the shore at Boulby.

Wilson, V. 1948. British Regional Geology, East Yorkshire and Lincolnshire. HMSO, 94p.
Black’s section is reproduced on page 38.

Historical Geology

Hunton, L. 1836. Remarks on a section of the Upper Lias and Marlstone of Yorkshire, etc. rans. Geol. Soc. London, 5, 215-220.
This is Hunton’s classic paper and includes his section at Boulby, undoubtedly the best by the early 19th Century geologists.

Torrens, H. S. and Getty, T. A. 1984. Louis Hunton (1814-1838). English pioneer in ammonite biostratigraphy. Earth Sciences History, 3, 58-68.
biography stressing the scientific importance of Louis Hunton.

Industrial History & Archaeology

Alum

Goldring, D. 2007. Louis Hunton and Loftus Alum Works. Cleveland Industrial Heritage, No. 21, 9-15.
Includes a copy of Hunton’s famous section emphasising points of industrial interest.

Hunt, A. et al. 2004. Loftus alum works, Redcar and Cleveland, Cleveland. An archaeological and historical survey. English Heritage, Survey Report A1/02/2004, 67p.
This is a major survey of Loftus Quarries with detailed plans covering the whole site. It is a pity that there is not more geology, that there are few survey levels and that information on the early 6 inches to 1 mile O. S. maps is missing.

Jecock, M. 2009. A Fading Memory: The North Yorkshire coastal alum industry in the light of recent analytical field survey by English Heritage. Industrial Archaeology Review, 31, 54-73.
General review of the alum industry.

Miller, I. 2002. The Manufacture of Alum: The Collated Evidence. Chapter 9 in ed. I. Miller, Steeped in History. The alum industry of North-East Yorkshire. NorthYorks Moors National Park Authority. 107-120.
A review that includes several references and photos of Hummersea going back to 1993.

Owen, J. S. 1986. Rutways before railways on the Yorkshire coast, with details of twelve sites between Saltburn and Scarborough. CIA No. 18, 23-32.
John Owen’s main record of rutways, etc.

Owen, J. S. (compiled by CIAS editorial board). 1998. Rutways and some other coastal features. (In Cleveland Ironstone (memorial volume)) 75-79. CIAS & NYMNP Authority, 103p
A compilation of John Owen’s finds.

Ironstone

Abandonment Plan (at Teesside Archives) Loftus (1 plan), abandoned 27/06/1959. Reference No. 15168.

Chapman, S. 1998. The Loftus mines, Skinningrove. Peter Tuffs Publications, 100pp.
Account of ironstone mining at Boulby and description of surface remains.

Tuffs, P. 1996. Catalogue of Cleveland Ironstone Mines. Peter Tuffs, Guisborough, 56p.
General details of Loftus mine.

Mini Geo-trail

Click here to view the Loftus Quarries Mini Geo-Trail »»

Surveyors

Denis Goldring 2011

©2011 Tees Valley RIGS Group.

PLEASE NOTE: Tees Valley RIGS Group cannot be held responsible for the content of external sites.

1. Site Description
2. Geology
3. Access
4. General Assessment:
5. Associated Sites
6. Safety Information
7. Supplementary Information
8. Geology
9. Industrial History and Archaeology
10. Literature References
11. Maps & Plans
12. Surveyors

Site Description

Grid Reference: NZ 755 195
BGS Sheet: 34
OS Sheet: 94
Forwarded as RIGS: 30/09/2003

Site Status: SSSI (RIGS Site Ref: RC5, Site No. 54 [ * Under Review * ]). Open access.

Please Note: The quarry is situated on private land, however spectacular views can be found by walking along the Cleveland Way and other adjacent public footpaths.

Description of Geodiversity: Extensive former alum quarry of great geological, scientific, historical and industrial archaeological interest. The Cleveland Way passes around the southern edge and along the top of the quarry back-wall that rises to over 200m O.D. The coastal scenery is impressive.

View of Boulby Quarries (foreground) showing Cowbar Nab near Staithes (background). Taken from the Cleveland Way above Sallow Tree Plain.

Geology

The quarries form the upper part of a virtually complete Jurassic succession ranging from the Lower Jurassic Redcar Mudstone Formation on the foreshore to the Middle Jurassic Saltwick Formation at the top. The quarried beds of interest to the alum industry constitute principally the Alum Shale Member of the Whitby Mudstone Formation. The beds exposed in the quarries are:

• Saltwick Formation: This forms the southern back-wall of the quarry, some 600m in length and up to 30m in height. It is formed predominantly of river channel sandstones. These exposures are difficult to reach and best examined more closely within the numerous fallen blocks.
• Dogger Formation: This Formation is about 1m thick and consists mainly of siliceous ironstone. It is sometimes absent as a result of washouts, and is now poorly exposed.
• Alum Shale Member: There are good exposures of the lower beds of shale (Whitby Mudstone Formation) which form the quarry floor especially at the western end.
• Reasons for SSI Status: Although the SSSI is named Boulby it actually includes both Boulby and Loftus Quarries. Two significant features, the murchisonae shale facies of the Dogger Formation and the finding of pterosaur remains in the Alum Shale, are at Loftus Quarries but it is likely that other reptilian remains were also found at Boulby.

Geomorphology: Several past and potential landslips and rockfalls can be seen and, in contrast, examples of slow, gradual sub-aerial cliff erosion.

Historical geology: This is the site of 19^th century measured sections by Rev. George Young, John Phillips, Lewis Hunton and others.

Industrial Archaeology:

• The quarry was a major alum site with at least two stages of development – mid-17^th to late-18^th century and late-18^th to late-19^th centuries. Across the site can be found the remains of calcining places, steeping pits, buildings, reservoirs, liquor conduits, etc. The stone revetments at the western end are most impressive.
• There are small ironstone trials of the Top Seam (Dogger Formation).
• The quarry is underlain by the extensive underground workings of the Main Seam (Cleveland Ironstone Formation) that are exposed along the sea cliff face.

Access

Access map for Boulby Quarries showing extent of SSSI and suggested parking.
(Click on map to enlage)

The easiest access is from the east along the Cleveland Way. A minor road off the A174 affords suitable parking.

General Assessment:

The quarry is an excellent venue for demonstrating Lower and Middle Jurassic geology, recent geomorphology, historical geology and industrial archaeology (alum and ironstone workings). The high cliffs require care.

Associated Sites

Boulby Sea Cliffs and Foreshore (North Yorkshire Heritage Coast, RC5, other reference 80.);
Loftus Alum Quarries (SSSI, other reference no. 53).

Safety Information

PLEASE NOTE: Due to the presence of high unfenced cliff faces we suggest that this site is not suitable for visits by unsupervised children. Please remain well away from the cliff edge and ensure any dogs are kept on a lead. Because of their unstable nature these cliffs must not, under any circumstances, be climbed.

Please follow the Country Code. Do not light fires. Take any litter home.

In situ fossils must not be collected, but their positions noted and details passed on to TVRIGS, a local museum or other similar body. Scattered fossils already weathered from the rock may be collected freely.

Supplementary Information

Geology

Structure: The succession is shown in the accompany section. The beds dip about 3° to the south.

Section through the cliff and quarry demonstrating the gentle dip of the beds.

Saltwick Formation (deltaic/alluvial): This forms the impressive back-wall of the quarry and consists principally of massive lenses of river channel sandstone. It is generally difficult to reach owing to fallen rock. Blocks, some extremely large, can be readily examined showing sedimentary structures such as cross-bedding and the imprints of plant remains.

Dogger Formation (marine incursion): This is about 1m in thickness and consists mainly of siliceous ooidal ironstone. However, at the eastern end it is described as ooidal siderite mudstone overlain by dark mudstone with similar mudstone nodules, as a clear result of lateral transition (Rastall and Hemingway, 1940). It is now poorly exposed. Blocks of ironstone can be examined that form a roughly laid wall by an old trial adit.

Alum Shale Member (marine): Some 10m of beds are exposed at various sub-quarry levels especially at the western (Sallow Tree Plain) end of the workings around the stone revetments. They consist of weathered, friable, grey, iron-stained, poorly bedded, flaky shale with vertically disposed jointing on the small scale. Fossils, chiefly poorly preserved belemnites, are uncommon but when seen may be present in clusters. Small acicular crystals of iron-stained gypsum are common. Occasional beds of lighter grey, calcareous, sometimes septarian, nodules can be found but, so far, Howarth’s (1962) detailed lithostratigraphic succession has not been elucidated. It is likely that the beds exposed belong to the lower part of the Alum Shale Member (the Hard Shale sub-unit) or even the upper part of the Mulgrave Shale Member.

Revetment walls at the west end of the site with Cowbar Nab in the background.

Geomorphology: The back-wall of the quarry has been subject to rock falls and there is now much debris at its foot. At the top, on the Cleveland Way there are open fissures with the cliffs being in a poor state. At quarry level on the seawards side there have been several landslips reported during and since the period of working that have carried away parts of the alum works and particularly the former tracks down to the shore. Elsewhere, such as for example at the Sallow Tree Plain (western end) steeping pits the cliff erosion has been limited. The ground between the Boulby and adjacent Loftus Alum Quarries illustrates how the original cliff profile looked.

Historical geology: Boulby Quarry and the sea cliffs beneath (making use of the tracks down to the shore) are where several 19^th century and, more recently, geologists such as Chowns made measured sections. That by Lewis Hunton (1836) is the most notable as he independently recognized the importance of collecting fossils in-situ, and relating the fossils found to the beds in which they occur bolstering the emerging concept of biostratigraphy.

View of Boulby Quarry and cliff as seen from Bias Scar toward Staithes.

Industrial History and Archaeology

Alum: The alum works was started in the 1650s at the eastern (Rockhole Hill) end of the quarry, redeveloped at the western (Sallow Tree Plain) end in 1784, and eventually closed in 1871. The alum house was about 0.5km to the south-east and, as well as tracks, there was a shaft and tunnel here connecting the house to the dock at Hole Wyke (see Boulby Sea Cliffs and Foreshore). The history and industrial archaeology of the alum works has received much attention in recent years (see references).

Ironstone: The Main Seam of the Cleveland Ironstone Formation has been worked extensively under the quarries from:

• (a) Boulby Mine, miners’ drift entrance at NZ 754 191, and
• (b) Grinkle Mine drift at NZ 762 177.

Boulby Ironstone Mine main haulage drift is now under the surface buildings of Cleveland Potash Mine, and the fan shaft is near the railway at NZ 757 179. The Main Seam typically consisted of a Top Block ~1m, Shale 0.3m and Bottom Block 0.7m. Waste was tipped in to the sea from a drift exit on the sea cliff at NZ 762 190. There are two trials of the Top Seam ironstone of the Dogger Formation, one within the quarries and one a short distance to the east (at NZ 758 190).

Current mining: Cleveland Potash Mine (at NZ 762 184) is of major importance to the local and national economies. Production started in 1973 and is of the order 1 million tonnes per year of potash (sylvinite) as well as rock salt (halite). The workings extend over a wide area that includes Boulby Quarry at a depth of around 1100m below sea level.

Literature References

Maps & Plans

Geological Survey Yorkshire Sheet IX SW, Rockcliff, scale 6 inches to 1 mile, 1878 (Ordnance Survey 1856).
Notes on the Lower Lias, Main Seam and Dogger. Shows 12 Steeping pits at Sallow Tree with cisterns, various buildings and reservoirs. Rockcliff (Pithill) building shown with various paths and reservoirs.

Geological Survey Yorkshire Sheet IXX NW, Boulby, Runswick & Kettleness, scale 6 inches to 1 mile, 1899 (Ordnance Survey 1856).
Shows outline plan of the alum house.

Ironstone Abandonment Plans (at Teesside Archives)

Boulby (1 plan), abandoned 2/7/1934. Ref. 11232
Grinkle (4 plans), abandoned 21/6/1934. Ref. 11261

Barrow, G. 1888. The Geology of North Cleveland. Mem. Geol. Survey, H.M.S.O., London, 101p.
Official memoir. Page. 9 shows the Main Seam ironstone section made on ‘the old road now slipped away’. Pages 42 and 43 show Dogger sections.

Chapman, S. K. 1975. Excavations at the Boulby Alum Works. Cleveland Industrial Archaeology Soc., 2, 23-47.
One of the first industrial archaeological accounts of an alum works.

Chapman, S. 2005. Boulby Alum Works Visit. C.I.A.S Newsletter No. 88, 11-17.
Industrial archaeological excursion guide.

Chapman, K. 2002. Boulby Alum Works. Chapter 6 in ‘Steeped in History’ (ed. Miller, I.), North Yorks Moors National Park Authority, 61-74.
A revised account of the 1975 work with additions and maps by English Heritage.

Fox-Strangways, C. 1892 The Jurassic Rocks of Britain, Volume 1. Yorkshire. Geol. Survey, H.M.S.O., London, 551p.
Similar to Barrow, 1888.

Goldring, D. 2001. Along the Scar. Peter Tuffs, Guisborough, 145p.
See pages 59 to 65.

Goldring, D. 2007. Louis Hunton and Loftus Alum Works. Cleveland Industrial Heritage No. 21, 9-15.
Includes a copy of Hunton’s famous section emphasising points of industrial interest.

Hunton, L. 1836. Remarks on a Section of the Upper Lias and Marlstone of Yorkshire, etc. Trans. Geol. Soc. London, 5, 215-220.
This is Hunton’s classic paper and includes his section at Boulby, undoubtedly the best by the early 19th Century geologists.

Jecock, M. 2009. A Fading Memory: The North Yorkshire coastal alum industry in the light of a recent analytical field survey by English Heritage. Industrial Archaeology Review, 31, 54-73.
General review of the alum industry, including several pictures of Boulby.

Marley, J. 1857. Cleveland Ironstone, etc. North of England IME Trans., 165-219.
Early, 19th Century ironstone working.

Miller, I. 2002. Steeped in History North York Moors NPA.

Osbourne, R. 1998. The Floating Egg Pimlico.

Phillips, J. 1829. Illustrations of the geology of Yorkshire, etc. Part 1 The Yorkshire coast. Private publication, York, 192p. (2nd Edition 1835 and 3rd Edition 1875, edit R. Etheridge).
Classic account. Section no. 9 shows some detail at Boulby.

Quinn, K. 2009. Boulby Alum: The works diary of George Dodds, (1772-1788). Cleveland Industrial Archaeology Society Research Report No. 9, 76p.
A detailed, primary historical account of operations at Boulby.

Rastall, R. H. & Hemingway, J. E. 1940. The Yorkshire Dogger, 1. The Coastal Region. Geol. Mag., 77, 177-197 & 257-275.
This is the only detailed description of the Dogger Formation for the Cleveland area. Pages 191 and 192 refer to Boulby sections and pages 263 and 264 to the petrography.

Tate, R. and Blake, J. F. 1876. The Yorkshire Lias. John Van Voorst, London, 475p.
Pages 132 and 133 show the ironstone section as seen on the path to the shore. Pages 170 and 175 detail the section in part of the Whitby Mudstone Formation.

Torrens, H. S. and Getty, T. A. 1984. Louis Hunton (1814-1838). English Pioneer in Ammonite Biostratigraphy. Earth Sciences History, 3, 58-68.
A biography stressing the scientific importance of Louis Hunton.

Tuffs, P. 1996. Catalogue of Cleveland Ironstone Mines. Peter Tuffs, Guisborough, 56p.
General details of the mines.

Young, G. and Bird, J. 1822. A Geological Survey of the Yorkshire Coast. Clark, Whitby, 332p. (2nd edition 1828).
The classic measured section at Boulby is on page 134 in the 2nd Edition with the Whitby Mudstone Formation divided into 3 subdivisions.

Surveyors

Denis Goldring 2011

©2011 Tees Valley RIGS Group.

1. Site Description
2. Site Map
3. Summary Evaluation of Site’s Value and Importance
4. Surveyors

Grid Reference NZ 631 146
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS Part of Guisborough Forest 30/09/2003

Site Description

Site Status SNCI

Brief Site Description Site 7 of 7. Disused alum quarry revealing exposures of Liassic Whitby mudstone and overlying Middle Jurassic Saltwick sandstone. Following abandonment after alum working, this quarry was used as a dump for ironstone spoil from mines around Slapewath. Shale was transported via an aerial ropeway.

Literature References Guisborough District Mines – Simon Chapman 2001

Site Map

Summary Evaluation of Site’s Value and Importance

Scientific Value
The sites in this group exhibit diverse examples of Liassic (Lower Jurassic) and Middle Jurassic deltaic deposits along with industrial archaeological remains.

Historical Value
Various industrial archaeological remains at the seven sites including ironstone extraction, the earliest alum quarries in England, and nineteenth century jet mining. Cass Rock Quarry was worked for alum shale between 1776 and 1805.

Aesthetic Value
From its vantage point high on the escarpment of the Cleveland Hills, Cass Rock Quarry provides an ideal vantage point giving commanding views of East Cleveland and the coast.

Educational Value
Situated beside the Cleveland Way to the east of Guisbrough Forest, Cass Rock is potentially a good site at which to examine Upper Liassic shales, Middle Jurassic sandstone, and explore the site of a former alum quarry. Nature has reclaimed this quarry and care should be exercised around vertical faces.

Surveyors

Andrew Carter, John Waring

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 749 162
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS 30/09/2003

Site Description

Site Status SNCI
Description of Geodiversity Upland river cutting through deltaic sandstone revealing river-cliffs and waterfalls. Exposures include Saltwick sandstone, Dogger and Whitby mudstone formations
Literature References

Site Map

Site Assessment

Surveyors

Andrew Carter, Andrew Cooper, Carl Rees-Davies

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 643 145
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS 30/09/03

Site Description

Site Status SNCI
Description of Geodiversity Upland river gorge revealing exposures of Saltwick sandstone with a beck cutting steeply through the profile
Literature References

Site Map

Site Assessment

Surveyors

Andrew Carter, Andrew Cooper and Carl Rees-Davies

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 715 182
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS

Site Description

Site Status
Description of Geodiversity River cliff exposures of massive Saltwick sandstone forming cliffs and escarpments
Literature References

Site Map

Site Assessment

Surveyors

Andrew Carter, Andrew Cooper

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 622 148
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS Part of Guisborough Forest 30/09/2003

Site Description

Site Status SNCI
Description of Geodiversity North facing escarpment revealing few exposures. Underlying geology is Staithes sandstone, Cleveland ironstone, Whitby mudstone overlain by the Saltwick sandstone formation. Old mine tips now wooded
Literature References Guisborough District Mines – Simon Chapman 2001
The Floating Egg – Roger Osbourne 1998

Site Map

Site Assessment

Surveyors

Denis Goldring

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 636 204
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS 30/09/2003

Site Description

Site Status SNCI
Description of Geodiversity Wooded erosional outlier revealing various exposures of Saltwick sandstone. Site also reveals workings from Jet mining and exposures of Cleveland ironstone
Literature References

Site Map

Site Assessment

Surveyors

Andrew Carter, Paul Murphy

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 653 152
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS 30/09/03

Site Description

Site Status SNCI
Description of Geodiversity Disused quarry revealing exposures of Saltwick sandstone and the base of the overlying Eller Beck formation
Literature References

Site Map

Site Assessment

Surveyors

Andrew Carter, Andrew Cooper