|Latitude & Longitude (WGS84):||51° 2' 38'' North , 3° 55' 30'' West|
|Latitude & Longitude (decimal):||51.04417,-3.92506|
|UK National Grid Reference:||SS653290|
|Köppen climate type:||Cfb : Temperate oceanic climate|
High Down Quarry is perhaps an ancient quarry. It is one of the few type localities which, although hundreds of years old, still have the potential to provide museum quality specimens. There is in existence a specimen on public display in Barnstaple Museum which is claimed to have been one of the original ones collected prior to 1785. The quarry listed by Natural England as an SSSI is opened in the Codden Hill Cherts and there appears to be no record of when the quarry was active.
The reader is encouraged to check the original first record in the literature. In The Transactions of the Philosophical Society of London for 1805, the mineral is recorded as being first recorded from a quarry many years ago by Dr. Wavell and that specimens were subsequently collected by Mr. Hatchett in 1796.
It is important to note that wavellite has been recorded in recent years from at least three quarries which are covered by the geographical name High Down and so it may not be this precise quarry that the type specimens came from. Indeed, the name High Down Quarry is a recent name not appearing on any map and in fact the Geological literature names the same quarry as Heddon Quarry. It is difficult to find maps of that era that record which quarries were in existence. Collectors might like to think carefully about where their specimen actually comes from and label it with a grid reference. The quarry behind High Down Cottages also yields wavellite specimens although collecting is currently not permitted. The quarry given SSSI status is close to Heddon which would be a better and much less confusing name. As wavellite occurs so close to the surface, it may have been found when the cottages were built or the local roads completed. Wavellite occurs as hemispheres and exceptionally rarely as complete spheres. The phosphate is possibly of fossil origin. The late David Cox, a resident of Bickington near Barnstaple, followed the outcrop of the Codden Hill Cherts and collected wavellite, and at a few locations variscite and cacoxenite, at nearly forty locations. David Cox's research collection is preserved in private hands. The quarry listed as the type locality is privately owned by The Castle Hill Estate. It is from this quarry that the late R.W. Barstow collected the specimens that he sold whilst dealing in minerals. The estate management will respond favourably to written requests to visit the quarry outside of the pheasant shooting season. Collecting also requires the written permission of Natural England who will check with the landowners. Consent for sensible non-commercial collecting may be given from 1st March to the end of August.
Devon Wavellite is a classic example of how mineral 'experts' have 'corrected' labels and reduced the scientific value of their material. Old specimens are labelled Devonshire, Barnstaple, Barnstable, Filleigh or South Molton. There are multiple North Devon locations that can produce specimens. The name High Down Quarry is a 20th-century name which has been applied to many old pieces making research difficult and in some cases pointless. If you study Wavellite under UV light you will see the fluorescence changes along the length of the crystal as mineral chemistry changes. Meaningful research is difficult as although 'High Down Quarry' is a prolific producer of material, no-one can be 100% certain where older relabelled specimens came from.
Regions containing this locality
|Eurasian Plate||Tectonic Plate|
|British Isles||Group of Islands|
|Devon and Cornwall metalliferous mining district, England, UK||Mining District|
Select Mineral List TypeStandard Detailed Strunz Dana Chemical Elements
6 valid minerals. 1 (TL) - type locality of valid minerals.
Detailed Mineral List:
| ⓘ Evansite ?|
Formula: Al3(PO4)(OH)6 · 6H2O
Colour: Milk white to creamy white, also various light to mid browns when stained by 'limonite'
Description: Many fracture surfaces in the Wavellite-rich mudstones are coated with a milky-white, amorphous material, often stained with 'limonite'. No crystalline structure has been observed in this material to date. Some fractures completely infilled with this material. Placement on the outside of wavellite balls places formation late in the mineralisation of the site. While still wet, the texture is somewhat greasy and reminiscent of fungal growth, but on drying, a fine, earthy texture is revealed, with a hardness of around 2.5 - 3 Tentative identification requires further investigation.
Reference: Alysson Rowan collection
| ⓘ Goethite|
Habit: Massive, encrusting
Colour: Brownish-black to golden-brown, often iridescent
Description: Appears as brownish-black, varnish-like films,dark brown to golden-brown encrustations and as fine, iridescent, botryoidal films.
Reference: Alysson Rowan collection
| ⓘ Gypsum|
Formula: CaSO4 · 2H2O
Habit: Euhedral, typically blocky, tabular, occasionally prismatic to 2mm. Also encrusting, anhedral.
Colour: Clear white to yellowish and brownish.
Description: Soft, delicate druses of fine gypsum crystals on some parts of the quarry north wall. Occasionally deposited on mosses and lichens.
Reference: Alysson Rowan collection
| ⓘ 'Limonite'|
Colour: Chocolate brown
Description: Limonite in botryoidal apprearence is present on the matrix.
Reference: Paul De Bondt collection
| ⓘ Quartz|
Habit: Druses of crystal points, otherwise massive.
Colour: White, transparent.
Description: Found as druses and massive veins in some fractures; A major quartz mass exists as a vein filling a fault that cuts the northern wall of the quarry - here the quartz encloses brecciated mudstones, and itself is somewhat brecciated.
Reference: Alysson Rowan Collection
Formula: AlPO4 · 2H2O
Reference: BMS Database
|ⓘ Wavellite (TL)|
Formula: Al3(PO4)2(OH,F)3 · 5H2O
Reference: Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 963; BMS Database
List of minerals arranged by Strunz 10th Edition classification
|Group 4 - Oxides and Hydroxides|
|Group 7 - Sulphates, Chromates, Molybdates and Tungstates|
|ⓘ||Gypsum||7.CD.40||CaSO4 · 2H2O|
|Group 8 - Phosphates, Arsenates and Vanadates|
|ⓘ||Evansite ?||8.DF.10||Al3(PO4)(OH)6 · 6H2O|
|ⓘ||Variscite||8.CD.10||AlPO4 · 2H2O|
|ⓘ||Wavellite (TL)||8.DC.50||Al3(PO4)2(OH,F)3 · 5H2O|
|Unclassified Minerals, Rocks, etc.|
List of minerals arranged by Dana 8th Edition classification
|Group 6 - HYDROXIDES AND OXIDES CONTAINING HYDROXYL|
|Group 29 - HYDRATED ACID AND NORMAL SULFATES|
|ⓘ||Gypsum||184.108.40.206||CaSO4 · 2H2O|
|Group 40 - HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES|
|ⓘ||Variscite||220.127.116.11||AlPO4 · 2H2O|
|Group 42 - HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN|
|ⓘ||Evansite ?||18.104.22.168||Al3(PO4)(OH)6 · 6H2O|
|ⓘ||Wavellite (TL)||22.214.171.124||Al3(PO4)2(OH,F)3 · 5H2O|
|Group 75 - TECTOSILICATES Si Tetrahedral Frameworks|
|Si Tetrahedral Frameworks - SiO2 with  coordinated Si|
|Unclassified Minerals, Mixtures, etc.|
List of minerals for each chemical element
|H||ⓘ Wavellite||Al3(PO4)2(OH,F)3 · 5H2O|
|H||ⓘ Variscite||AlPO4 · 2H2O|
|H||ⓘ Gypsum||CaSO4 · 2H2O|
|H||ⓘ Evansite||Al3(PO4)(OH)6 · 6H2O|
|O||ⓘ Wavellite||Al3(PO4)2(OH,F)3 · 5H2O|
|O||ⓘ Variscite||AlPO4 · 2H2O|
|O||ⓘ Gypsum||CaSO4 · 2H2O|
|O||ⓘ Evansite||Al3(PO4)(OH)6 · 6H2O|
|F||ⓘ Wavellite||Al3(PO4)2(OH,F)3 · 5H2O|
|Al||ⓘ Wavellite||Al3(PO4)2(OH,F)3 · 5H2O|
|Al||ⓘ Variscite||AlPO4 · 2H2O|
|Al||ⓘ Evansite||Al3(PO4)(OH)6 · 6H2O|
|P||ⓘ Wavellite||Al3(PO4)2(OH,F)3 · 5H2O|
|P||ⓘ Variscite||AlPO4 · 2H2O|
|P||ⓘ Evansite||Al3(PO4)(OH)6 · 6H2O|
|S||ⓘ Gypsum||CaSO4 · 2H2O|
|Ca||ⓘ Gypsum||CaSO4 · 2H2O|
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
298.9 - 323.2 Ma
Age: Pennsylvanian (298.9 - 323.2 Ma)
Stratigraphic Name: Clackmannan Group
Reference: Asch, K. The 1:5M International Geological Map of Europe and Adjacent Areas: Development and Implementation of a GIS-enabled Concept. Geologisches Jahrbuch, SA 3. 
|Namurian - Famennian|
315 - 372.2 Ma
|Teign Valley Group|
323.2 - 358.9 Ma
|Paleozoic sedimentary rocks|
Age: Mississippian (323.2 - 358.9 Ma)
Lithology: Sedimentary rocks
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.