Whidborne gave a composite description of certain specimens from the Upper Devonian of Pilton and other localities which he grouped together and ascribed to the Carboniferous species P. (Buxtonia) scabriculus Mart. (Whidborne, 1897, 170, pi. xx, figs. 16–18, pi. xxi, fig. 12), but he considered that it was difficult to distinguish some of them from those which he ascribed to Strophalosia productoides. We cannot agree with his reference of any of them to Martin's Carboniferous species. The best preserved and first example [H. 286] which he figured (1897, pi. xx, fig. 16) is a pedicle-valve from “Smoking House Lane”. It has a transversely subquadrate shape with subrectangular cardinal angles not produced; the body is strongly arched longitudinally but only moderately convex transversely, and it has a weak median longitudinal depression, but descends steeply on each side to the smalt ears; it is covered by regular continuous rounded costae of equal size, about fifty in number, some of which bifurcate at about one-third to two-thirds their length, and very few of them show any small swellings on their course as in P. scabriulus; a few faint narrow concentric rugae are traceable on the posterior third of the body producing weak coarse reticulation; the umbo is very broad, rounded and incurved, projecting over the hinge-line; the ears, which are much depressed but not sharply marked off from the body, are triangular in shape and are crossed by a few narrow concentric rugae which bifurcate somewhat irregularly before reaching the hinge-line; a few large coarse spinose tubercles or spine-bases lie near the junction of the body with the ears. This pedicle-valve is sufficiently preserved to indicate a distinct species, for which the name porteri is proposed.
Review of strongly-coupled composite dark matter models and lattice simulations
