Brachiopoda from the Lower Lias, Green Ammonite Beds, of Dorset

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Abstract
I. Introduction. Brachiopods are rare in the Green Ammonite Beds of Dorset and are represented by only three species, two of which belong to the Discinidæ and one to the Rhynchonellidæ. The specimens, with one exception, are of small size and are usually much crushed and distorted. The most abundant species is Scalpellirhynchia scalpellum (Quenstedt), which is found mainly in beds 129 and 130, just below the Middle Lias, while a few scattered specimens occur below in beds 122–126 and 127. This species occurs in the lower part of the Lias δ of Württemberg, but has not been previously recorded from this country, owing probably to the lack of careful collecting in other areas of Liassic deposits. An investigation of the internal structure of S. scalpellum was made by grinding transverse and longitudinal sections of specimens that had been previously heated to redness and embedded in plaster cubes when cool. A full description of this method is given elsewhere (Muir-Wood, 1934). One pedicle valve of a Discinisca of exceptionally large size was obtained from bed 130. One small specimen of Discinisca holdeni was obtained from the Upper Limestone, bed 129a, and a second specimen from the Red Band, bed 126a of Stonebarrow Cliff. All the material was collected by Dr. W. D. Lang and is preserved in the British Museum of Natural History collection. The specimen [B52300] consists of the conical valve only, of which all but the innermost layer of the shell is missing. The shape is approximately circular