Fig. 7
From: Monoplacophorans and the Origin and Relationships of Mollusks
Early Paleozoic distribution of Monoplacophora (Tryblidacea) across Sepkoski's (1987) environmental zones. Zone 1 nearshore (tidally influenced); Zone 2 nearshore (subtidal); Zone 3 offshore (turbulent); Zone 4 middle shelf (below wave base); Zone 5 shelf edge; Zone 6 deep water. Data compiled from over 150 publications listing the occurrence of Monoplacophora in Early Paleozoic facies (Stuber and Lindberg 1989)