| Computer Code: |
HY |
Preferred Map Code: |
H |
| Status Code: |
Full |
| Age range: |
Aptian Age (KP)
— Aptian Age (KP) |
| Lithological Description: |
In the western Weald, the formation comprises mainly fine- to medium-grained, sparsely glauconitic sands, sandstones and silts, locally pebbly, with calcareous or siliceous cement in beds or lenses in some areas. Some clay interbeds, including Fuller's Earth. In Kent and eastern Sussex the formation comprises, alternating sandy limestones ("Ragstone") and glauconitic sandy mudstones (Hassock). |
| Definition of Lower Boundary: |
The base is taken at the incoming of fine- to medium-grained sands above the silty or sandy clays of the Atherfield Clay, and is generally sharply defined. See also Hoes Farm Member. |
| Definition of Upper Boundary: |
The upper boundary is placed at the unconformable to disconformable contact at the base of heterogeneous sediments of the Sandgate Formation. Generally the boundary is identified by the upward change from sparsely glauconitic sands of the Hythe Formation to glauconitic medium-grained sands and silts with pebbles of the individual members of the Sandgate Formation. This boundary is not easy to recognize in much of Sussex. There is generally an unconformable to disconformable contact. |
| Thickness: |
18 to 100m. |
| Geographical Limits: |
As an arcuate outcrop around Weald of Kent, Surrey and Sussex. In the subcrop as far north as the London-Brabant ridge. |
| Parent Unit: |
Lower Greensand Group (LGS)
|
| Previous Name(s): |
Hythe Beds
(-975)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Hoes Farm Borehole SU91NE/19 [SU9808 1962] near Petworth. Partial section of the formation from 28.4 to 72.00m depth. Bristow et al. (1987). Young and Lake (1988, p.28, Figure 7). |
| Reference Section |
Sunken lane near Nutbourne, Sussex. Partial succession. |
| Reference Section |
Bognor Common Quarry, West Sussex. Partial succession of the lower part of the formation. |
| Type Section |
Coastal exposures around Mill Point, Folkestone, Kent. Casey (1961); Smart et al. (1966, p.78). |
| Reference(s): |
| Smart, J G O, Bisson, G and Worssam, B C. 1966. Geology of the Country around Canterbury and Folkestone. Memoir of the Geological Survey of Great Britain, Sheets 289, 305 and 306 (England and Wales). |
| Casey, R, 1961. The stratigraphical palaeontology of the Lower Greensand. Palaeontology, Vol.3, 487-621. |
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. |
| Ruffell, A H. 1992 Correlation of the Hythe Beds Formation (Lower Greensand Group: early-mid Aptian), southern England. Proceedings of the Geologists' Association, Vol.103, 273-291. |
| Bristow, C R, Morter, A A, and Wilkinson, I P. 1987. The stratigraphy and palaeontology of the Lower Greensand of the Hoes Farm Borehole, near Petworth, Sussex. Proceedings of the Geologists' Association, Vol. 98(3), 217-227. |
| Drew, F. 1864. The geology of the country between Folkestone and Rye, including the whole of Romney Marsh (Sheet 4). Memoir of the Geological Survey of the United Kingdom. |
| Rawson, P F. 1992. Cretaceous, 355-388 in Duff, P McL D and Smith, A J (editors), Geology of England and Wales. (London: Geological Society.) |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E285
E286
E287
E288
E289
E300
E301
E305
E317
E318
E319
E332
E333
E334
|
