Hodgson How Quarry, near Portinscale, is a historically important Ordovician graptolite locality. Its Kirk Stile Formation mudstones preserve flattened fossils including Azygograptus lapworthi. Steep, unstable rock and uncertain current access make this a site for a carefully arranged geological visit, with landowner permission required before entry or collecting.
FIND FREQUENCY: ♦♦♦ – Graptolites are documented, but the historical rating is not a guarantee of present-day availability. Exact bed information is valuable.
CHILDREN: ♦ – Steep slabs and unstable quarry faces make this unsuitable for children’s collecting or family scrambling.
ACCESS: ♦♦♦ – A small roadside quarry west of Portinscale. Confirm the route, safe parking and permission before visiting; no public right through the workings is established here.
TYPE: – Disused quarry in dark mudstone and siltstone; steep exposures and loose shale.
DIRECTIONS
♦ Hodgson How Quarry lies west of Portinscale, near Keswick. Use the A66 and a current map to locate the quarry area before arranging access.
♦ The original approach from Keswick described a small road on the right about 300 m beyond the Portinscale turn, with the quarry a further 250 m along it. These are historical route details, not confirmation of an authorised entrance or parking place.
♦ Ask the landowner about access and where it is safe and permissible to leave a vehicle. Do not obstruct the road, enter a private track or cross a barrier on the assumption that the quarry is open.
♦ BGS graptolite locality: NY 2437 2364. Original UK Fossils location: 54.60178°N, 3.17616°W.
FOSSIL HUNTING
The best-supported named fossil at Hodgson How is Azygograptus lapworthi. BGS illustrates a specimen from the quarry, GSM 46365, and nineteenth-century accounts also record the species here. Azygograptus has a single principal branch, or stipe. In a compressed fossil the outline and small repeated thecal structures are more useful identification features than colour alone.
Graptolites were colonial marine animals whose remains settled into fine sediment. Here they are flattened on rock surfaces and may be distorted by later deformation. The original visit described brown fossils in brown or orange layers between blue-grey rock. That is a useful historical field observation, but staining and cleavage do not identify a species or prove that every similarly coloured layer is fossiliferous.
The 2004 visit distinguished harder rock on the right, vegetation-obscured rock in the centre and more fissile, steeply inclined beds on the left or south-south-east side. These are observations of separate parts of the old exposure, not three named geological beds. Their visibility may have changed, and they do not justify entering farther beneath a face or climbing a loose slope.
The old identification of a four-branched form as Tetragraptus quadribrachiatus has not been independently confirmed for this exact quarry. It is best treated as a historical identification until the specimen is examined. A current generic reassignment in a taxonomic reference is not sufficient to relabel an unexamined photograph, and no reliable modern survey supports a promise of two common species at the site.
During an authorised visit, examine only material that can be reached from a secure position away from the faces, and follow the landowner’s collecting conditions. Photograph a surface before disturbing it, include a scale, and record whether the rock was in place or already loose. If removal is permitted, wrap thin shale pieces individually and keep counterpart surfaces together. Do not undercut the face or prise out a lower slab.
The quarry also has an important microscopic fossil record, including acritarchs used to correlate the rocks. These were recovered and identified through laboratory study; they are not conspicuous fossils to look for on a hand specimen. Their value lies in the geological information they preserve, alongside the visible graptolites.
Significant discoveries, geological research and conservation milestones at Hodgson How Quarry.
1875 – Azygograptus is formally described
Nicholson published the genus Azygograptus and its type species Azygograptus lapworthi. Later systematic work associates the original material with Hodgson How, but neither an exact collection date nor an identified surviving original type is established.
1894 – Marr records the quarry’s graptolite
J. E. Marr listed Azygograptus lapworthi from Hodgson How in his account of the Skiddaw Slates, providing an explicit nineteenth-century locality record.
1913 edition – The quarry is illustrated in a mining history
Postlethwaite’s mining-history volume included two photographs of Hodgson How, looking south-east and east-north-east. The edition date does not establish when the photographs were taken.
1991 – A systematic revision informs the age interpretation
Beckly and Maletz revised Azygograptus and related forms. Their work underpins the later geological memoir’s gibberulus-age interpretation for Hodgson How.
1995 – The microscopic fossil assemblage is published
Cooper and colleagues documented the quarry’s Stelliferidium assemblage in a regional synthesis, adding acritarch evidence to the graptolite record.
2004 – BGS brings the locality evidence together
The geological memoir integrated the figured Azygograptus lapworthi specimen, the quarry locality register and the acritarch correlation within the Kirk Stile Formation. It retained uncertainty over correlation with the two sandstone lenses.
2018 – The original-type uncertainty is clarified
The revised Treatise retained Azygograptus and documented Hodgson How as the original type locality, while stating that the original type material had not yet been identified.
GEOLOGY
Hodgson How exposes the Kirk Stile Formation of the Skiddaw Group. These are Ordovician rocks, traditionally described as Arenig. The BGS locality register places the quarry graptolites in the victoriae or gibberulus Biozone, while the memoir’s narrative favours the latter. Retaining the alternative recognises the limits of the available exact-locality records.
The formation is dominated regionally by dark mudstone and siltstone, commonly finely laminated or very thinly bedded, with local sandstone lenses. These sediments accumulated in a deep marine setting, where quiet settling was interrupted by sediment carried by turbidity currents. Graptolite remains became preserved within the finer sediment, while microscopic organic-walled fossils provide a second means of comparing the sequence with other exposures.
The rocks were later deformed and cleaved. Bedding marks the original sedimentary layers, whereas cleavage is a later splitting fabric and need not follow the same planes. The steep inclination reported during the original visit helps explain the slabby, unstable nature of the old quarry; it should not be converted into a modern measured structural survey.
BGS correlates the quarry’s acritarch-bearing beds with one of two sandstone lenses in a wider Kirk Stile Formation section. The published figure deliberately leaves that choice unresolved. It does not show that both lenses are exposed in Hodgson How, and it supplies no measured quarry-bed thickness. Likewise, the formation’s regional thickness of 1500–2500 m is not the height of this small exposure. The detailed section below separates exact fossil records, uncertain regional correlation and the historical visitor observations.
Detailed geology, graptolites and the uncertain sandstone correlation at Hodgson How
SKIDDAW GROUP
Kirk Stile Formation
Rock and age. The quarry is assigned to the Kirk Stile Formation, a regional succession of dark, thinly laminated to very thinly bedded mudstone and siltstone, locally associated with sandstone lenses. The traditional regional age term is Arenig, within the Ordovician. The exact graptolite locality record gives the victoriae or gibberulus Biozone; the narrative discussion favours gibberulus. Neither a precise numerical age nor a complete measured quarry thickness is established.
Deep-water sediment and later deformation. Fine sediment settled in a marine basin and was interrupted by material carried in turbidity currents. Later cleavage and deformation modified the original fabric. Bedding and cleavage may differ in orientation, so a split slab is not automatically a complete sedimentary bed. The regional formation thickness of approximately 1500–2500 m must not be applied to Hodgson How.
Graptolite-bearing beds, NY 2437 2364. BGS locality 88 records Azygograptus lapworthi, illustrated as specimen GSM 46365 in figure 11l. The conservative victoriae or gibberulus assignment appears both in the locality table and the specimen caption. GSM 46365 is a figured specimen, not a demonstrated holotype, neotype or other type specimen. No numbered fossil bed or exact host-bed thickness is given.
Acritarch-sampled beds, NY 2442 2361. A separate point within the quarry yielded a Stelliferidium aff. pseudoornatum microflora. The two grid references locate different samples rather than two distant localities. In the BGS correlation diagram, these beds are associated with one of two sandstone lenses within the Kirk Stile Formation; the alternative is unresolved.
Exact microscopic assemblage. The Hodgson row of the BGS figure records acanthomorph acritarchs, Polygonium spp., Stelliferidium spp., Striatotheca microrugulata, Striatotheca principalis parva, Veryhachium trispinosum and Stelliferidium aff. pseudoornatum. Questioned records are Coryphidium bohemicum?, Veryhachium lairdii? and Vogtlandia flosmaris?. These names and uncertainties reproduce the published quarry row; they are laboratory records rather than a hand-specimen collecting list.
Alternative sandstone correlations: S′ or S″. The regional Lorton Fells diagram links the Hodgson sample to either a lower lens labelled S′ or a higher lens labelled S″. These are alternative correlations, not two confirmed exposures or successive beds in this quarry. The regional figure’s scale does not yield a numerical thickness or vertical separation for the Hodgson beds. Loweswater and Hope Beck formations shown elsewhere in the regional framework are not added to the quarry sequence.
Harder right-hand exposure. The 2004 field account described hard rock on the right as apparently unfossiliferous. This is a historical observation of one part of the exposure, not a formal unit or proof that the formation is barren there.
Vegetation-obscured centre. Trees and other plants concealed the central exposures at the original visit. Vegetation marks a gap in what could be observed, not a separate geological horizon or an inferred change of formation.
Fissile left-hand and south-south-east exposure. The original guide described more readily splitting beds inclined at roughly 60 degrees, with brown or orange layers between blue and grey rock and reported graptolites. This records the 2004 appearance, not a new survey or an access recommendation. Colour differences may reflect weathering and do not independently establish a biozone.
Loose shale and scree. Material already dislodged from the face was reported in the original visit. Its mixed, displaced position does not recover its precise parent bed. Steep slabs and the danger of sudden sliding mean that these descriptions must not be read as advice to approach, undercut or break the faces.
Taxonomic and type-locality limits. Azygograptus lapworthi is the type species of Azygograptus. The modern Treatise associates the original material with Hodgson How but states that the original type material has not yet been identified. The old Tetragraptus quadribrachiatus identification lacks independent confirmation at the quarry; a later reassignment of that nominal species to Eotetragraptus cannot by itself reidentify the visitor material.
References.
Cooper and colleagues (2004), The Skiddaw Group of the English Lake District, figures 11 and 17 and Appendix 2 locality 88.
BGS Lexicon: Kirk Stile Formation.
Maletz, Zhang and VandenBerg (2018), Treatise Online 107, Azygograptus account.
Marr (1894), Notes on the Skiddaw Slates.
Beckly and Maletz (1991), Ordovician Azygograptus and Jishougraptus.
SAFETY
The old guide documents beds inclined at about 60 degrees and warns that removing support from below can cause rock to slide down suddenly. Do not hammer or prise material from the face, undercut beds, or stand beneath steep slabs. A helmet does not make an unstable exposure safe.
Keep back from quarry edges and loose slopes. Vegetation can conceal uneven ground and detached rock, and wet mudstone or shale may be slippery. Avoid the quarry in poor conditions, and do not enter if a safe route or permission is uncertain.
This is not suitable for children’s collecting or casual scrambling. Any authorised examination of loose material should take place from a secure position away from the faces, with another person aware of your plans.
EQUIPMENT
For an agreed visit, bring sturdy boots, a hand lens, a camera and a scale. A map and weatherproof clothing are essential for locating the site and returning safely.
If the landowner permits limited collecting of loose material, carry tissue or other soft wrapping and a rigid box for fragile shale. Do not take rock-breaking equipment as an invitation to work the quarry face; the steep bedding makes undercutting especially dangerous.
CLEANING AND TREATING
Graptolite-bearing shale can split or flake, and the fossil may be little more than a delicate film on the surface. Start with light dry brushing and avoid vigorous washing, acids, powered preparation or scraping across the fossil.
Keep the two sides of a split specimen together and preserve its label and locality notes. Allow damp material to dry slowly at room temperature. A potentially important or unusually complete specimen is best left unprepared for specialist examination; do not coat it routinely with varnish or glue.
IDENTIFY YOUR FINDS
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FURTHER READING
BGS: The Skiddaw Group of the English Lake District
BGS Lexicon: Kirk Stile Formation
Treatise Online (2018): graptolite systematic descriptions
Beckly and Maletz (1991): Ordovician graptolite revision
Historic photograph catalogue: Hodgson How Quarry
ACCESS RIGHTS
Ask the landowner before entering Hodgson How Quarry or collecting specimens, and follow any conditions and current signs. Its roadside position and historical use by geologists do not establish unrestricted public access.
Arrange safe parking without obstructing the road or entrances. If permission or a safe route cannot be established, do not enter the workings. No invitation to excavate, hammer a face or remove specimens is implied by this guide.
It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions‘
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