Acutirostris - spinosa Zone

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Definition: From first appearance of Rugia acutirostris to immediately below first appearance of Rugia spinosa (Johansen & Surlyk, 1990). Brachiopod density and diversity are high through the zone (Johansen & Surlyk, 1990).

Biostratigraphical correlation: The zone equates with the basal part of the B. lanceolata Zone of the traditional macrofossil biozonal scheme.

Lithostratigraphical correlation: The zone equates with the lower part of the Sidestrand Chalk Member (Johansen & Surlyk, 1990).