Computer Code: |
HHS |
Preferred Map Code: |
HH |
Status Code: |
Pending Upgrade |
Age range: |
Toarcian Age (JT)
— Toarcian Age (JT) |
Lithological Description: |
A brown, shelly, bioclastic limestone, parallel- bedded and cross-bedded, interpreted to have been deposited in a shallow marine tidal channel. |
Definition of Lower Boundary: |
The base displays a change upward from sands or sandstones of undivided Bridport Sand Formation into bioclastic limestone. |
Definition of Upper Boundary: |
The top is generally a non-sequence displaying a sharp change upward from bioclastic limestone to cream or grey shelly or ooidal limestone or calcareous mudstone of the Inferior Oolite, elsewhere it may be conformable, displaying a change up into sandy mudstone of undivided Bridport Sand Formation. |
Thickness: |
Up to 27 m thick. |
Geographical Limits: |
The Yeovil-Crewkerne area of south Somerset, where it wedges out laterally into undifferentiated Bridport Sand Formation. |
Parent Unit: |
Bridport Sand Formation (BDS)
|
Previous Name(s): |
Ham Hill Stone [Obsolete Name and Code: Use HHS]
(-3468)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Ham Hill, also known as Hamdon Hill, Yeovil, Somerset. |
Reference(s): |
Prudden, H C. 1967. Excavations in the Yeovil Sands at Yew Tree Close, Yeovil. Proceedings of the Dorset Natural history and Archaeological Society, Vol. 88, 42-43. Shelfmark 00479. |
Richardson, L. 1919. The Inferior Oolite and contiguous deposits of the Crewkerne district (Somerset). Quarterly Journal of the Geological Society of London, Vol. 74, 145-173. |
Buckman, S S. 1889. On the Cotteswold, Midford and Yeovil Sands, and the division between the Lias and the Oolite. Quarterly Journal of the Geological Society of London, Vol. 59, 445-458. |
Woodward, H B. 1887. Note on the Ham Hill Stone. Proceedings of the Bath Natural History and Antiquarian Field Club, Vol 6, 182-184. |
Wilson, V, Welch, F B A, Robbie, J A, and Green, G W. 1958. Geology of the country around Bridport and Yeovil. Memoir of the Geological Survey of Great Britain, Sheets 327 and 312 (England and Wales). |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E312
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