(Riedel and Sanfilippo, 1970)

The top of the zone is defined by the evolutionary transition from Dorcadospyris dentata to Dorcadospyris alata and is coincident with the lower limit of the Dorcadospyris alata Zone.

Events included in the zone are:

- Tm Eucyrtidium diaphanes

- Liriospyris stauropora -> Liriospyris parkerae

- Tm Carpocanopsis favosa

- Tm Didymocyrtis prismatica

- Tm Carpocanopsis cingulata; Bm Carpocanopsis cristata

- The lower limit of the zone is approximately synchronous with Tm Lychnocanoma elongata

The base of the zone is defined by the morphotypic first appearance of Calocycletta costata and is coincident with the upper limit of the Stichocorys wolffii Zone.

Reference slides R 20.1, R 20.2 and R 20.3 from Sample 85-573B-123, 61-63 cm.; R 21.1, R 21.2 and R 21.3 from Sample 85-573B-13-CC.