Overview 
Named the Green Ammonite Bed after the limestone nodules that are found here were found to contain ammonites fossilised with green calcite filling in the septal chambers. Name was first used in 1863 by E.C.H. Day.

An alternative name for this division, proposed in 1911 by Woodward & Ussher, was Wear Cliff Beds, due to it making up the coastal feature known as 'Wear Cliffs' located between Golden Cap and Seatown.

The Green Ammonite Bed (averaging 50-100ft at the coast), is best studied between St. Gabriel's Mouth and Seatown,  via  Golden Cap, where it forms the lower cliffs. It consists of 100ft of clays with three irregular limestone layers. Towards the top of the division, the beds become more sandy, eventually becoming a sandy loam in the uppermost 18ft.

The Red Band (Bed 126) at 1ft thick, is a bed of reddish weathered limestone concretions and marls that form a good marker in the middle of this division. Beneath this bed, and midway between it and the Belemnite Stone, is the Lower Limestone (Bed 123a), a band of small hard limestone nodules. Midway between the Red Band and the lowest tier of the Three Tiers Bed, is the Upper Limestone (Bed 129), formed by two bands of shaly limestone separated by some 3ft of blue-grey clay.

This division marks the base of the Upper Pliensbachian (Domerian) stage.

Fossils 

Below the Red Band the ammonites Aegoceras, Androgynoceras, Tragophylloceras loscombi, Prodactylioceras davoei and Liparoceras are common, as are gastropods Coelodiscus, Nucula and Parainoceramus, especially around the Lower Limestone bed. Towards the bottom of the division the Belemnites Hastites and Passaloteuthis are abundant. Above this band the ammonites Oistoceras and Liparoceras are common, as are some Brachiopods. In the top 10ft of the division, the ammonite Amaltheus stokesi starts to appear. Within the Red Band the gastropod Nucula is found, as is the crinoid Balanocrinus.

 Zones and sub-zones 


Zone

Subzone

Beds

Amaltheus margaritatus Amaltheus nodifer

131-132

Prodactylioceras davoei Oistoceras figulinum

127-130

Liparoceras bechei

125-126

Androgynoceras lataecosta

122g-124

Androgynoceras maculatum

122a-122f


Beds and fossils 


Bed

Name

Geology

132 - Loam's & loamy clays
131 - Loam's & loamy clays
130 - Loamy clay
129 Upper Limestone 2 bands of shaly limestone separated by 3' blue-grey clay. 35ft thick at Golden Cap.
128 - Clay
127 - Clay
126 Red Band 1' reddish limestone band (a grey centre with reddish weathered top and bottom) containing gastropod Nucla sp and the crinoid Balanocrinus. 33ft thick at Golden Cap.
125b - -
125a - Flat red nodules
124 - -
123s - Blue-grey nodules
123r - -
123q - Blue-grey nodules
123o - -
123n - -
123m - Flat red nodules in clay
123l - Clay
123k - Clay
123j - Clay
123i - Clay
123h - Clay
123g - Clay
123f - Clay
123e - Clay
123d - Clay
123c - Clay
123b - Clay
123a Lower Limestone
[see image below]		 Discontinuous band of small hard limestone nodules containing the gastropods Nucla sp, Coelodiscus sp  and Parainoceramus sp,  and the ammonites Lataecosta sp  and Tragophylloceras loscombi. 23ft thick at Golden Cap.
122g - Clays
122f - Blue-grey nodules
122e - Blue-grey nodules
122d - Blue-grey nodules
122c - Clays
122b - Clays
122a - Clays


Bed photographs

Cliff faces under Stonebarrow Hill showing the limited exposure of the Green Ammonite Bed. Unless a landslip occurs, the bed is difficult to examine from this location.

gc-15.jpg (75786 bytes)

Taken from Ridge Cliff on the eastern side of Seatown, showing the eastern side of Golden Cap. At sea level, the Belemnite Marls are nearly all covered by water at high tide. The prominent limestone band seen half way up the cliff face, is the upper bed of the Three Tiers Bed. Between them appears the Green Ammonite Bed. This forms the cliff face making up Wear Cliffs going towards Seatown. 

Taken at sea level, midway between Seatown and Golden Cap, the Green Ammonite Bed forms the feature known as Wear Cliffs, at this point, although they do tend to be covered by slipped material from the top of the cliff. The darker (and wet) Belemnite Marls can be seen on the right hand side of the photo. At the time the photo was taken, the tide had ebbed about 15% out from a high tide. A visit to the same location, several months later, and the Belemnite Marls were covered in several feet of sand and shingle.

bed-123a.jpg (104014 bytes)

The 'Lower Limestone' bed 123a, is a discontinuous band of small, hard limestone nodules, some 25 feet above the Crumbly bed & Pyritic Marls (bed 120) of the Belemnite Marls.

 Other Green Ammonite Bed references