List of Sites of Special Scientific Interest in Hertfordshire explained

Hertfordshire is a county in eastern England. It is bordered by Bedfordshire to the north, Cambridgeshire to the north-east, Essex to the east, Buckinghamshire to the west and Greater London to the south. The county town is Hertford. As of 2018, the county has a population of 1,184,400[1] in an area of 634sqmi.[2]

As of July 2019, there are 43 sites designated within this Area of Search, 36 of which have been designated for their biological interest and 7 for their geological interest.[3] In England the body responsible for designating SSSIs is Natural England, which chooses a site "because of its flora, fauna, or geological or physiographical features".[4]

Key

Interest

Other classifications

Sites

Site namePhotographAreaPublic
access
LocationOther
classifications
MapCitationDescription
scope=rowAldbury Nowers 19.8haYES Tring
51.812°N -0.6219°W
HMWT[5] CitationThe site hosts the flowers of chalk grassland and has butterfly habitats with several different species of butterfly including the Duke of Burgundy, hairstreaks and the Essex skipper. There are also large areas of woodland and calcareous grassland.[6] [7]
scope=rowAlpine Meadow 0.8haYES Berkhamsted
51.7826°N -0.5677°W
HMWT[8] CitationThis steeply sloping small meadow is a rare example of unimproved chalk grassland. Grass species include upright brome, false brome and sheep's fescue, and there are many orchids, especially common twayblade and common spotted orchid.[9]
scope=rowAmwell Quarry 37.1haYES Great Amwell
51.7978°N -0.0045°W
HMWT,[10] SPA, SPA[11] Ramsar[12] CitationThis is an internationally important site for wintering wildfowl, and is Britain's most important site for dragonflies. Plants include marsh dock and hairlike pondweed, both nationally rare. Amwell has a quarter of all British species of molluscs.[13]
scope=rowAshridge Commons & Woods 627.3haYESLittle Gaddesden
51.8116°N -0.5871°W
CAONB,[14] NTCitationThs site is mainly semi-natural vegetation, with has extensive areas of woodland, grass and scrub. There are many species of breeding birds, including some which are rare nationally, such as firecrests. Other species which are rare in Hertfordshire are common redstart, nightingale and wood warbler.[15]
scope=rowAshwell Springs 0.3haYES Ashwell
52.0421°N -0.1497°W
CitationThe site consists of a series of freshwater springs, which provide a habitat for cold water, invertebrate animals, some of which are rare. The site is particularly important for flatworms, including Crenobia alpina and the Polycelis felina.[16]
scope=rowBenington High Wood 20.7haYES Benington
51.8952°N -0.1339°W
CitationThe site is ancient woodland, described by Natural England as "one of the best remaining examples in the county of the pedunculate oak-hornbeam of the ash-maple variety". Shrub species include field maple and hazel, with a higher ground flora diversity in clearings and rides.[17]
scope=rowBlagrove Common 5haYES Sandon
51.9868°N -0.0704°W
HMWT[18] CitationThe site is one of the few areas of unimproved marshy grassland in east Hertfordshire. It is crossed by a stream and has a rich diversity of vegetation, including a variety of orchids.[19] Kestrels often hunt mice and voles, which are common on the site.
scope=rowBricket Wood Common 75.5haYES Bricket Wood
51.6964°N -0.3664°W
CitationThe common is a remnant of a lowland heath, with much it on the heavy soils of boulder clay which have poor drainage and wet habitats. There are also areas of ancient woodland and dry heath. In drier heath areas there are heather, purple moor-grass and heath milkwort.[20]
scope=rowCastle Lime Works Quarry 1.4haNO South Mimms
51.7087°N -0.2227°W
GCR[21] CitationNatural England states: "This reveals extensive piping in the top of the chalk resulting from solution at the Chalk - Tertiary sediment interface. Believed to have formed during the Tertiary and Pleistocene, it is the finest exposure of clay-filled pipes in the Chalk Karst of England."[22]
scope=rowCroxley Common Moor 39.6haYES Croxley Green
51.6425°N -0.4363°W
LNR[23] CitationThe site is mainly grass heathland with some ancient woodland and hazel coppice. Over 250 species of plants have been recorded, including sheep sorrel, common bent and sheep's fescue. There are many ant hills made by yellow meadow ants.[24]
scope=rowDownfield Pit, Westmill 0.3haYES Ware
51.8308°N -0.0437°W
CitationThe site provides an example of the complex sequence of Pleistocene gravels and clays laid down by the River Thames when it flowed through the Vale of St Albans before the river was diverted south by the Anglian ice age around 450,000 years ago.[25]
scope=rowFrogmore Meadows 4.6haYES Chenies
51.6796°N -0.5247°W
CAONB,[26] HMWT,[27] CitationThe site has marshy areas and fens next to the river, damp grassland and drier, more acidic areas. The river bank has water voles, and damp areas are dominated by meadow foxtail and Yorkshire fog, with some marsh marigold and marsh bedstraw.[28]
scope=rowGreat Hormead Park 15haYES Great Hormead
51.9432°N 0.0616°W
CitationThe site is coppiced ancient woodland on boulder clay. It has diverse tree species, including wych elm and hornbeam, resulting in a rich ground flora. Dog's mercury is dominant over most of the woodland floor, with plants such as angelica sylvestris and tufted hair grass in wetter areas.[29]
scope=rowHertford Heath 29.1haYES Hertford Heath
51.7813°N -0.0372°W
&
HMWT[30] CitationThe heath is dominated by heather, and there are grass snakes and slow worms. Sphagnum mosses and creeping willow are found in wetter areas. Ponds support the rare water violet and a rich invertebrate fauna such as great crested and smooth newts, the water spider and eight species of dragonfly.[31]
scope=rowHillcollins Pit 0.2haYES Furneux Pelham
51.9211°N 0.0954°W
GCR[32] CitationThis disused gravel pit is the type site for the Westland Green Gravels, which were laid down by the ancestral River Thames 1.6 to 1.8 million years ago, and which show the river's ancient course.[33]
scope=rowHunsdon Mead 34.2haYES Harlow
51.7797°N 0.0541°W
HMWT[34] CitationThis is unimproved grassland which is subject to winter flooding. Notable grass species include meadow brome and the quaking grass briza media, and there are other unusual flora such as pepper saxifrage and green-winged orchid.[35]
scope=rowKnebworth Woods 128.8haYES Stevenage
51.8857°N -0.2172°W
CitationThe wood is ancient in origin and ecologically diverse. The dominant trees are oak and hornbeam. Ponds have unusual plant species, and the site is rich in fungi and bryophytes. Breeding birds include nightingales.[36]
scope=rowLittle Heath Pit 1.2haYES Potten End
51.7633°N -0.5278°W
GCR,[37] NT[38] CitationThe lowest layer is gravel dating to the beginning of the Pleistocene 2.6 million years ago. A higher layer of gravel was laid down some 20,000 years ago, when the last ice age was at its maximum, and the site was cold tundra like western Siberia today.[39]
scope=rowMoor Hall Meadows 24haYES Ardeley
51.9211°N -0.0674°W
CitationThe site has a variety of types of meadows, with marshy grassland being the most extensive. Its rich flora makes it one of the most important grassland sites in the county. There is also a small ancient woodland which has a variety of breeding birds.[40]
scope=rowMoor Mill Quarry, West 0.2haNO How Wood
51.7119°N -0.3506°W
GCR[41] CitationThe pit displays the advance of ice during the Anglian glaciation around 450,000 years ago, which diverted the Thames south to its present course. The site is regarded by Natural England as of fundamental importance as the only one which demonstrates the diversion of the Thames from its pre-Anglian course.[42]
scope=rowNorthaw Great Wood 224.3haYES Cuffley
51.7228°N -0.1483°W
LNR[43] CitationThe site has one of the county's most extensive areas of ancient hornbeam woodland, with other trees including oak and silver birch. Glades, streams and springs add to the biodiversity.[44]
scope=rowOddy Hill and Tring Park 36haYES Tring
51.789°N -0.6473°W

51.7837°N -0.6561°W
RHPG.[45] CitationThis is one of the most extensive areas of unimproved chalk downland in Hertfordshire. The site has diverse grass and flowering plant species. Orchids include common spotted-orchid, common twayblade, greater butterfly-orchid and southern marsh-orchid.[46]
scope=rowOughtonhead Lane 1haYES Hitchin
51.9552°N -0.2959°W
GCR[47] CitationThe site probably dates to the Hoxnian interglacial 420,000 to 300,000 years ago. It was then a marsh fed by springs, and it has a tufa which contains fossil land snails and mammal bones which show the climate and local environmental conditions.[48]
scope=rowPatmore Heath 8.5haYES Albury
51.912°N 0.0965°W
HMWT[49] CitationThe site is home to a large amount of dry grass, as well as marshy-areas. Much of the turf is dominated by Deschampsia, as well as occurrences of Anthoxanthum odoratum. Uncommon plants are heath rush and heath grass. There are a wide variety of dragonfly, including the emperor dragonfly.[50]
scope=rowPlashes Wood 73.2haYESStandon
51.8669°N 0.0058°W
CitationThe site is mainly oak and hornbeam woodland near the northern limit of its natural distribution. It has varied ground flora on soils from damp heavy clay to light gravels. There are also ponds and extensive clearings dominated by bracken, and other flora including hoary cinquefoil.[51]
scope=rowRedwell Wood 52.6haYES South Mimms
51.7081°N -0.2459°W
CitationThe site has ancient and secondary woodland, heath and scrub. The woodland canopy is dominated by pedunculate oak. Ground flora include bluebells and enchanter's-nightshade, while heathland species include heather and the rare creeping willow.[52]
scope=rowRoughdown Common 3.7haYES Hemel Hempstead
51.7402°N -0.485°W
CAONB[53] CitationThis is one of the few examples of unimproved calcareous grassland in Hertfordshire. The dominant grasses are meadow fescue and meadow oat-grass, and there are colonies of orchids. It is the only site in the county where common juniper regenerates naturally.[54]
scope=rowRye Meads 60.3haYES Rye House
51.776°N 0.0061°W
Ramsar,[55] SPA RSPB, HMWT[56] CitationPart of this site is an ancient flood meadow which has a variety of habitats including reedbed, marshy grassland and fen. It is grazed by ponies and water buffalo. There are also ponds which have kingfisher, snipe, green sandpiper, shoveler, gadwall and tufted duck.[57]
scope=rowSarratt Bottom 3.5haNO Sarratt
51.6794°N -0.5102°W
CitationThe site is a meadow beside the River Chess. It is an example of damp grassland which has been traditionally managed for grazing. There are also areas of swamp and marsh. The main plants in grassland areas include sweet vernal grass and meadow foxtail, and marsh horsetail and common spike-rush are common in damper areas.[58]
scope=rowSawbridgeworth Marsh 6.2haYES Sawbridgeworth
51.8209°N 0.1634°W
EWT[59] CitationThe site is a river valley marsh close to the River Stort, which has a varied wetland flora. Grazing and cutting of the marsh in rotation maintain biological diversity. The site also has an important wetland fauna and many moth species.[60]
scope=rowSherrardspark Wood 74.4haYES Welwyn Garden City
51.8102°N -0.2172°W
LNR[61] CitationThe site is an ancient semi-natural sessile oak and hornbeam wood on acid soils. There are also swallowholes fed by streams, and a woodland ride provides a habitat for invertebrates.[62]
scope=rowTewinbury 7.3haNO Tewin
51.8095°N -0.1679°W
HMWT[63] CitationThe site borders the River Mimram. It has alluvial meadows and marshes which are rare in lowland Britain. There are areas of swamp and tall fens, with plants including butterbur and angelica. Otters have been observed on the riverbank, in possibly the only site in the county.[64]
scope=rowTherfield Heath 146.5haYES Therfield
52.0423°N -0.0549°W
LNR,[65] SM[66] [67] CitationThis site is described by Natural England as describing some to the richest chalkland in England. It is unimproved pasture which has a wide variety of plants including the rare pasque flower. There is a diverse insect fauna.[68]
scope=rowThorley Flood Pound 17.3haYES Thorley
51.8434°N 0.1615°W
HMWT[69] CitationHabitats include tall wash grassland, which is now rare, marsh and waterlogged grassland. It has a wide variety of plant species, including reed sweet-grass and meadowsweet. There are flowers such as fen bedstraw and early marsh orchid. Breeding birds include snipe and water rails.[70]
scope=rowTring Reservoirs 100haYES Tring
51.8135°N -0.6683°W

HMWT[71] CitationThese four reservoirs are on the sites of ancient marshes, and their diverse fauna and flora include some dating back to their marshland origins. The site is important for breeding and wintering birds, including nationally important numbers of shovelers. The site is also significant for invertebrates.[72]
scope=rowTring Woodlands 24.1haYES Tring
51.7812°N -0.6721°W
CAONB[73] CitationThe wood has a rich flora, showing that it is well established. It is one of the best examples of semi-natural beech woodland in Hertfordshire. Plants include woodruff, wood anemone and dog's mercury, and there is a variety of woodland birds.[74]
scope=rowTurnford and Cheshunt Pits 174.4haYES Cheshunt
51.709°N -0.0186°W
SPACitationThis site includes ten former gravel pits, which are of national importance for wintering gadwalls and shovelers. It is also valuable for invertebrates, especially grasshoppers and bush-crickets.[75]
scope=rowWain Wood 19haYES Preston
51.9155°N -0.2858°W
CitationThe wood lies on a north-east facing slope of decalcified boulder clay. The woodland area is also home to pedunculate oak and Quercus petraea, with much of the south of the area consisting of acidic grassland. There are many butterfly species, including Thecla quercus.[76]
scope=rowWater End Swallow Holes 11.1haYESWelham Green
51.7239°N -0.2206°W
CitationThe site covers more than fifteen sinkholes, the only ones in chalk which are a permanent feature of the landscape. Next to the holes is a swamp area of willow carr which is biologically important, and in deep water there is reed sweet-grass. The site also has areas of woodland and grassland.[77]
scope=rowWestwood Quarry 0.1haNO Watford
51.6823°N -0.4523°W
GCR[78] CitationThis site throws light on the early history of the River Thames, when it flowed through the Vale of St Albans, before it was diverted south to its present course during the Anglian Ice Age around 450,000 years ago.[79]
scope=rowWhippendell Wood 66.7haYESWatford
51.6687°N -0.4455°W
CitationThis is ancient woodland, and the main trees are oak, ash, hazel and hornbeam. Ground flora include Yorkshire fog, bluebells and honeysuckle. There are diverse species of fungi, invertebrates and birds.[80]
scope=rowWormley-Hoddesdonpark Wood North 143.9haYES Hoddesdon
51.7589°N -0.0425°W

NNR,[81] WT, NCR,[82] HMWT,[83] SAC[84] CitationThe site is oak and hornbeam on acid gravel. The ground flora is diverse, including dog's mercury and yellow archangel. Small ponds and streams are important for bryophytes, and invertebrates include the green tiger beetle.
scope=rowWormley-Hoddesdonpark Wood South 196.2haYES Cheshunt
51.7441°N -0.0735°W
NNR,[85] NCR,[86] SACCitationThe site is oak and hornbeam woodland mainly on London clay. Plants in the variable ground flora include brambles, wood anemones and bluebells. Other habitats include marshland and acidic grassland.

See also

Notes and References

  1. Web site: Herts Insight. People and Place. 23 July 2019.
  2. Web site: Area Measurements. Hertfordshire Local Information System. 10 February 2015. https://web.archive.org/web/20150210194001/http://www.hertslis.org/geog/areameas/. 10 February 2015. live.
  3. Web site: Designated Sites View - Hertfordshire. Natural England. 23 July 2019.
  4. Web site: Guidelines for selection of biological SSSIs . Joint Nature Conservation Committee . 12 January 2016 . https://web.archive.org/web/20160123202250/http://jncc.defra.gov.uk/page-2303 . 23 January 2016 . live.
  5. Web site: Aldbury Nowers. Herts and Middlesex Wildlife Trust. 11 January 2016. https://web.archive.org/web/20150905160000/http://www.hertswildlifetrust.org.uk/reserves/aldbury-nowers. 5 September 2015. live.
  6. Web site: Aldbury Nowers . Natural England . 21 February 2006 . dead . https://web.archive.org/web/20090320005726/http://www.english-nature.org.uk/citation/citation_photo/1005932.pdf . 20 March 2009.
  7. Web site: Aldbury Nowers. Herts and Middlesex Wildlife Trust. 2011-01-07. https://web.archive.org/web/20110723234311/http://www.hertswildlifetrust.org.uk/NatureReserves/Local/aldburynowers. 2011-07-23. dead.
  8. Web site: Alpine Meadow. Hertfordshire and Middlesex Wildlife Trust. 21 December 2014. https://web.archive.org/web/20141221133546/http://www.hertswildlifetrust.org.uk/reserves/alpine-meadow. 21 December 2014. dead.
  9. Web site: Alpine Meadow citation . Sites of Special Scientific Interest . Natural England . 21 December 2014 . dead . https://web.archive.org/web/20160304073344/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000438.pdf . 4 March 2016.
  10. Web site: Amwell. Hertfordshire and Middlesex Wildlife Trust. 19 December 2014. https://web.archive.org/web/20150419222334/http://www.hertswildlifetrust.org.uk/reserves/Amwell. 19 April 2015. dead.
  11. Web site: Lee Valley. Joint Nature Conservation Committee. 16 January 2016. https://web.archive.org/web/20161026182919/http://jncc.defra.gov.uk/page-2047-theme=default. 26 October 2016. live.
  12. Web site: Lee Valley. Ramsar Sites Information Service. 19 December 2014. https://web.archive.org/web/20141220000404/https://rsis.ramsar.org/ris/1037. 20 December 2014. live.
  13. Web site: Amwell Quarry citation. Sites of Special Scientific Interest. Natural England. 19 December 2014. https://web.archive.org/web/20150924140213/http://www.sssi.naturalengland.org.uk/citation/citation_photo/2000384.pdf. 24 September 2015. live.
  14. Web site: Ashridge Commons and Woods citation . Sites of Special Scientific Interest . Natural England . 4 January 2016 . dead . https://web.archive.org/web/20160304051209/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000452.pdf . 4 March 2016 .
  15. Web site: Ashridge Commons & Woods citation . Sites of Special Scientific Interest . Natural England . 19 December 2014 . dead . https://web.archive.org/web/20160304051209/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000452.pdf . 4 March 2016 .
  16. Web site: Ashwell Springs citation . Sites of Special Scientific Interest . Natural England . 12 January 2015 . dead . https://web.archive.org/web/20160304052907/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000593.pdf . 4 March 2016 .
  17. Web site: Benington High Wood citation . Sites of Special Scientific Interest . Natural England . 3 January 2015 . dead . https://web.archive.org/web/20160303222006/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000632.pdf . 3 March 2016 .
  18. Web site: Blagrove Common. Hertfordshire and Middlesex Wildlife Trust. 12 January 2015. dead. https://web.archive.org/web/20141223015213/http://oldhmwt.cubik.co.uk/NatureReserves/Local/Blagrove+Common. 23 December 2014.
  19. Web site: Blagrove Common citation . Sites of Special Scientific Interest . Natural England . 12 January 2015 . dead . https://web.archive.org/web/20160304035044/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000847.pdf . 4 March 2016 .
  20. Web site: Bricket Wood Common citation . Sites of Special Scientific Interest . Natural England . 7 December 2014 . dead . https://web.archive.org/web/20160303234831/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000694.pdf . 3 March 2016 .
  21. Web site: Castle Lime Works Quarry (Karst). Joint Nature Conservation Committee. 11 January 2016. https://web.archive.org/web/20160304055029/http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=1125. 4 March 2016. live.
  22. Web site: Castle Lime Works Quarry citation . Sites of Special Scientific Interest . Natural England . 15 January 2015 . dead . https://web.archive.org/web/20160304060949/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000741.pdf . 4 March 2016 .
  23. Web site: Croxley Common Moor . Local Nature Reserves . Natural England . 13 March 2013 . 10 December 2014 . dead . https://web.archive.org/web/20140809035055/http://www.lnr.naturalengland.org.uk/Special/lnr/lnr_details.asp?C=0&N=&ID=589 . 9 August 2014 .
  24. Web site: Croxley Common Moor citation . Sites of Special Scientific Interest . Natural England . 10 December 2014 . dead . https://web.archive.org/web/20160304045158/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000788.pdf . 4 March 2016 .
  25. Web site: A Geological Conservation Strategy for Hertfordshire. Hertfordshire RIGS Group. 2003. 43. 4 February 2015. dead. https://web.archive.org/web/20150924021515/http://www.geo-east.org.uk/newsletters/herts/a_geological_strategy_for_hertfordshire2003.pdf. 24 September 2015.
  26. Web site: Frogmore Meadows citation . Sites of Special Scientific Interest . Natural England . 11 December 2014 . dead . https://web.archive.org/web/20160303223850/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1002647.pdf . 3 March 2016 .
  27. Web site: Frogmore Meadow. Herts and Middlesex Wildlife Trust. 11 December 2014. https://web.archive.org/web/20141211113249/http://www.hertswildlifetrust.org.uk/reserves/frogmore-meadow. 11 December 2014. live.
  28. Web site: Frogmore Meadows citation . Sites of Special Scientific Interest . Natural England . 11 December 2014 . dead . https://web.archive.org/web/20160303223850/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1002647.pdf . 3 March 2016 .
  29. Web site: Great Hormead Park citation. Sites of Special Scientific Interest. Natural England. 19 February 2015. https://web.archive.org/web/20160303225022/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1002244.pdf. 3 March 2016. live.
  30. Web site: Hertford Heath. Herts and Middlesex Wildlife Trust. 15 February 2015. https://web.archive.org/web/20150411065406/http://www.hertswildlifetrust.org.uk/reserves/hertford-heath. 11 April 2015. dead.
  31. Web site: Hertford Heath citation . Sites of Special Scientific Interest . Natural England . 15 February 2015 . dead . https://web.archive.org/web/20160304002956/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001447.pdf . 4 March 2016 .
  32. Web site: Furneux Pelham Gravel Pit (Hillcollins Pit) (Quaternary of the Thames). Joint Nature Conservation Committee. 18 February 2015. https://web.archive.org/web/20150219042008/http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=450. 19 February 2015. live.
  33. Web site: Hillcollins Pit citation. Sites of Special Scientific Interest. Natural England. 18 February 2015. https://web.archive.org/web/20160304043955/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1002467.pdf. 4 March 2016. live.
  34. Web site: Hunsdon and Eastwick Meads. Herts & Middlesex Wildlife Trust. 11 January 2016. https://web.archive.org/web/20160914185534/http://www.hertswildlifetrust.org.uk/reserves/hunsdon-and-eastwick-meads. 14 September 2016. dead.
  35. Web site: Hunsdon Mead citation . Sites of Special Scientific Interest . Natural England . 22 December 2014 . dead . https://web.archive.org/web/20160304023953/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1003531.pdf . 4 March 2016.
  36. Web site: Knebworth Woods citation . Sites of Special Scientific Interest . Natural England . 3 January 2015 . dead . https://web.archive.org/web/20150924124830/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001506.pdf . 24 September 2015 .
  37. Web site: Little Heath Pit (Quaternary of the Thames). Joint Nature Conservation Committee. 11 January 2016. https://web.archive.org/web/20160818051202/http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=486. 18 August 2016. live.
  38. Web site: Little Heath Pit citation. Sites of Special Scientific Interest. Natural England. 25 February 2015. https://web.archive.org/web/20150924124846/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001529.pdf. 24 September 2015. live.
  39. Information board on the site
  40. Web site: Moor Hall Meadows citation. Sites of Special Scientific Interest. Natural England. 3 January 2015. https://web.archive.org/web/20150924131541/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1002523.pdf. 24 September 2015. live.
  41. Web site: Moor Mill Quarry (Quaternary of the Thames). Joint Nature Conservation Committee. 11 January 2016. https://web.archive.org/web/20160304110712/http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=451. 4 March 2016. live.
  42. Web site: Moor Mill Quarry, West citation. Sites of Special Scientific Interest. Natural England. 7 December 2014. https://web.archive.org/web/20150924135416/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1006291.pdf. 24 September 2015. live.
  43. Web site: Northaw Great Wood Country Park. Local Nature Reserves. Natural England. 14 March 2013. 22 March 2015. https://web.archive.org/web/20150210191923/http://www.lnr.naturalengland.org.uk/Special/lnr/lnr_details.asp?C=21&N=&ID=1193. 10 February 2015. live.
  44. Web site: Northaw Great Wood citation. Sites of Special Scientific Interest. Natural England. 23 December 2014. https://web.archive.org/web/20160303224158/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1000830.pdf. 3 March 2016. live.
  45. Web site: Tring Park. English Heritage. 23 December 2014. https://web.archive.org/web/20150113013957/http://list.english-heritage.org.uk/resultsingle.aspx?uid=1000218#. 2015-01-13. dead.
  46. Web site: Oddy Hill and Tring Park citation. Sites of Special Scientific Interest. Natural England. 2 June 2016. https://web.archive.org/web/20160304075509/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1005717.pdf. 4 March 2016. live.
  47. Web site: Oughtonhead Lane, Hitchin (Quaternary of East Anglia). Joint Nature Conservation Committee. 11 January 2016. https://web.archive.org/web/20160304093713/http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=2247. 4 March 2016. live.
  48. Web site: A Geological Conservation Strategy for Hertfordshire. 2003. Hertfordshire RIGS Group. dead. https://web.archive.org/web/20150924021515/http://www.geo-east.org.uk/newsletters/herts/a_geological_strategy_for_hertfordshire2003.pdf. 2015-09-24.
  49. Web site: Patmore Heath. Herts and Middlesex Wildlife Trust. 11 December 2014. https://web.archive.org/web/20141213020646/http://www.hertswildlifetrust.org.uk/reserves/patmore-heath. 13 December 2014. dead.
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