View source for Hagenowia (blackmorei) Horizon (Subzone)

This interval of the ''G. quadrata'' Zone has only been formally recognised in southern England.

'''Base''': In southern England, the base of the horizon is placed at Telscombe Marl 4 (Mortimore, 1986; Young & Lake, 1988).

'''Top''': In southern England, the top of the horizon is placed at the Lancing Flint (Mortimore, 1986).

'''Range of index species''': The index, ''Hagenowia blackmorei'' ranges from the top of the ''O''. ''pilula'' Zone to within the middle of the nominate Horizon / Subzone (Mortimore, 1986).

'''Key fauna''':
{| class="Wikitable"
| Porifera:      ||    ''Retispinopora lancingensis''
|-
| Anthozoa:   ||    ''Coelosmilia regularis''
|-
| Brachiopoda: || ''Cretirhynchia intermedia''
|-
| ||''Isocrania egnabergensis'' (large)
|-
| ||''Kingena blackmoorei''
|-
| ||''Orbirhynchia bella''
|-
| Bivalvia:    ||     ''Inoceramus sarumensis''
|-
| ||''                        I. subsarumensis''
|-
| Belemnoidea: ||''Belemnitella mucronata''
|-
| ||''Gonioteuthis quadrata''
|-
| Echinoidea:   ||  ''E.'' sp. (large form of Gaster, 1924)
|-
| ||''E.'' sp. (small form of Gaster, 1924)
|-
| ||''Hagenowia blackmorei''
|}
'''Faunal abundance & preservation''': This interval is quite poorly fossiliferous, the index species and some of the allied fauna are also quite small and inconspicuous.

'''Bio-horizons''': The index is quite inconspicuous, comprising fragments of the distinctively elongated rostrum. ''Retispinopora lancingensis'' and ''Isocrania egnabergensis'' are also small fossils. In southern England, there are two successive acmes of ''Echinocorys'', the first, comprising the 'large forms' of Gaster (1924), are large, evenly rounded, hemispherical morphotypes with a sharply defined, flat base. These are overlain by an acme of the 'small forms' of Gaster (1924), comprising morphotypes that resemble ''Echinocorys cincta'' and ''E. depressula'' from the underlying ''O. pilula'' Zone (Young & Lake, 1988). There is a local acme of ''Belemnitella'' at this horizon in the Salisbury area, which seems to be more widely developed at a comparable level in the ''G. quadrata'' Zone in Northern Ireland (Bailey ''et al''., 1983; Wilson & Manning, 1978).

'''Age''': Campanian

[[category:Standard zonation | 026]]