Rowe (1900) - Holaster planus Zone
Biostratigraphical correlation: Equates with an interval within the S. plana Zone of current usage. Rowe (1900) placed the base of this zone at the Bridgewick Marl (Wood, WH/91/35R). Rowe's account about where the top of this zone should be placed suggests two alternatives, either within the Lewes Nodular Chalks (= South Street Beds of Mortimore, 1986), or at the base of the Cuilfail Zoophycos, both in the higher part of the S. plana Zone as currently understood (Wood, WH/95/31R).
Lithostratigraphical correlation: Equates with the lower and middle part of the Lewes Nodular Chalk Formation of southern England.