AbstractThe measures between the Soft Bed and the Middle Band Coal of Yorkshire and the equivalents of these seams in Lancashire, the Bassy and Lower Foot Mines, are remarkably uniform. The horizons of two thinLingulabands, first described by the author from Huddersfield, may be traced, usually as marine shale, northward to Bradford and Burnley, southward to near Sheffield, westward to St. Helens and south‐westward to Goyt's Moss, Derbyshire, where the lower band has yieldedGastriocerassp. The bands ofLinguladivide the measures into three small‐scale cyclic units of sedimentation which contain non‐marine lamellibranchs throughout much of their vertical extent.Studies of faunas from localities which yielded the types ofCarbonicola fallax, C. proteaandC. haberghamensisWright are described in some detail. At Feniscowles, near Darwen (type locality for the first two species) it is shown that with passage upward into slightly more coarse grained beds in the lower cyclic unit the small shells of theC. fallaxgroup show an upward increase in H/L ratio with some evidence of a split into two species.The non‐marine succession, of Honley, near Huddersfield, is regionally summarized. Attention is drawn to a maximum ofCarbonicola rectilinearisTrueman and Weir in the lower part of the lower cyclic unit and to the marker horizons ofCarbonicola discusEagar andC. haberghamensisWright in the upper part of the middle unit.Carbonicola pilleolum, the new species described, covers variants previously referred to, or compared with,C. sulcata