508 J. W. Jackson — Occurrence of Productus humerosus. 



2. P. sublcevis, de 3Com, highly convex, characterized by a very 

 definite median sinus (without a central spinous ridge) and concentric 

 ribbing on umbonal region. 



3. P. aff. christiani, de Kon., narrow and broad forms, with 

 indistinct central spinous ridge (represented in some by a row of 

 well-spaced spine-bases, which very late on are situated on a ridge) ; 

 indistinct, or no, median sinus ; concentric ribbing as in last. 



4. P. christiani, de Kon., large, broad forms, with distinct central 

 spinous ridge commencing near beak, sometimes in a sinus; concentric 

 ribbing as last. 



The same four variations are present at Caldon Low, but of the 

 specimens I have examined the majority appertain to var. (2) ; 

 whereas at Dove Dale the dominant form is (3). 



From what I have seen of the Breedon (Leicester) specimens they 

 seem referable to (3) or (4) ; but being mainly casts, it is difficult to 

 be sure. Some certainly show evidence of a median ridge. 



Examples of the variant (1) (which I here term P. aff. sublcevis), 

 are figured by Delepine (" Calc. Carb. Belg.," Mem. Facult. Cath. 

 Lille, 1911, pi. xiv, figs. 3, 3a), and by Yaughan (Q.J.G.S., 

 vol. lxxi, pi. vii, fig. 8, 1915). 



Among the other Dove Dale Brachiopods the most interesting are : 

 a giant papilionaceous Chonetes (190 + mm. along the hinge-line) ; 

 a remarkable variety of Productus mesolobus (quite unlike the form 

 from the " Brachiopod-beds ") ; and a striking form of a semi- 

 reticulate Productus with narrow, highly-convex umbonal region, 

 square-cut flanks, strong reticulation near the beak, and with the 

 stria? thickened at intervals by spine-bases. This form seems to be 

 near P. doulaghensis, Yaughan (Q..J.G.S., vol. lxxi, p. 47, pi. vii, 

 fig. 7), but has straighter sides and a flatter venter. 



.The following also occur: Bielasma sp., Athyris glabristria, 

 Reticularia lineata, Spirifer pinguis, S. striatus, S. attenuatus, 

 S. planatus, S. cf. convolutus, Camerophoria pleurodon, C. (?) tumida, 

 Pugnax acuminatus var. plicatus, Orthotetes sp., Schizophoria 

 resupinata (large), S. gibbera, Productus margaritaceus, P. cora, 

 P. cf. concinnus, P. " pustulosus' 7 , Chonetes aff. comoides. 



The Gastropods belong to the genera Euomphalus, Straparollus, and 

 Phymatifer {Ph.pugilis) ; Bellerophon also occurs ; the Lamellibranchs 

 are Pterinopecten eximius, Pt. granosus, and Conocardium aliforme. 



With a few exceptions the assemblage of forms recalls, in part, 

 the fauna of the "Brachiopod-beds" of the Midland area, allocated 

 by Sibly to the sub-zone D 2 (Zo?isdalia subzone), (Q.J.G.S., 1908). 



Many of the forms occur in knolls of both Tournaisian and Yisean 

 age, and are such as were regarded by Yaughan as indicating 

 conditions only (Q.J.G.S., lxxi, p. 13). It would appear, from the 

 abundance of Productus humerosus with such a fauna in Dove Dale, 

 that this species has every right to be included as a knoll-form, and 

 the species therefore loses its value as a zonal index. It is of 

 interest to note that this species (as P. sublcevis) is recorded from beds 

 at Vise containing Pugnax acuminatus and Phymatifer pugilis. The 

 massif at Vise is now regarded as equivalent to the "Brachiopod- 

 beds " of the Midland. 



