Maxwell, P.A. 2009 Cenozoic Mollusca, New Zealand Inventory of Biodiversity, D.P. Gordon (ed), Canterbury University Press: Christchurch, N.Z, 1 (p.236)
Powell, A.W.B. 1931 Waitotaran faunules of the Wanganui System: and descriptions of new species of Mollusca from the New Zealand Pliocene, Records of the Auckland Institute and Museum, 1 (p.110) Original Description
Key to Geographical Ranges
The symbols K.A.C.F.M.An. are used to indicate the geographical range of the species.
They have been adopted to give an approximation of the range of each species within New Zealand.
Aupourian - Kaipara Harbour, north around North Cape, encompassing the Three Kings Islands and south to East Cape
Cookian - Lower North Island and the northern part of the South Island