Article: A non-marine ostracod fauna from the Coal Measures of Durham and Northumberland

The occurrence and ostracod fauna of the Hopkins Band, Lower Anthraconaia modiolaris Zone, of the Lower Coal Measures of Northumberland and Durham are described. In this Band the ostracod Geisina arcuata is associated with five species of Carbonita, newly recorded, and variants of the non-marine lamelli-branchs Anthracosia regularis, Carbonicola oslancis, Naiadites productus, and Anthraconaia modiolaris. A vertical sequence of six faunal phases is recognized in this Band and is compared with that previously recorded from an equivalent stratigraphical horizon in the Yorkshire Coal Measures.Vertical changes in the number of ostracod species and number of moults present in the Hopkins Band are recorded and explained in terms of the changing conditions in the environment of deposition. Certain ecological requirements of the ostracods are suggested.In the systematic description of the fauna a lectotype for Geisina arcuata and a new species Carbonita claripunctata are proposed. The species Carbonita humilis, C. evelinae, C. pungens, and C. inflata are briefly described and their morphology and stratigraphical distribution discussed.Lectotypes for Carbonita agnes, C. evelinae, C. humilis, C. inflata, C. pungens, and C. rankiniana are designated by F. W. Anderson in a postscript.