The present paper summarizes some of the recent work on the stratigraphy of the Middle Carboniferous in the south-eastern and eastern parts of European USSR., work which throws new light on the position of the Moscovian stage in the Carboniferous succession. The Moscovian stage is at the present generally accepted as corresponding to the whole of the Middle Carboniferous (Danshin, Schwetzow, Khimenkow, and others), but the evidence of a break at the base of the Moscovian beds near Moscow justifies us in putting the question—is the Moscovian stage to be regarded as corresponding to the whole series of Middle Carboniferous deposits or was the deposition of the Moscovian series of beds preceded by erosion not only of part of the Lower Carboniferous, but also of part of the Middle Carboniferous? At the same time the new data concerning the character of the boundary of the Moscovian with the Upper Carboniferous tends to prove that at this boundary also there are signs of a hiatus.

Recently there was discovered in a quarry at Kiplingcotes Station, East Yorkshire, an iron-stained and sometimes nodular chalk, which appears to be a lenticular patch, varying from 0 to 18 inches in thickness. It is situated in a spur between two lime kilns and contains an abundant fauna. The rock bears more resemblance to some of the bands of iron-stained nodules that form the Chalk Rock of Surrey than to the characteristic hard limestone. The quarry is apparently fairly near the top of the Holaster planus zone and has, for a long time, been known to be very fossiliferous.

From time to time measurements of the rate of sedimentation in salt marsh areas have been made, but few detailed figures are available. The fullest account is that by F. J. Richards (1) for the Dovey Marshes. Others have been made at Blakeney by F. W. Oliver (2) and, recently, measurements have been made in Denmark by Dr. Niels Nielsen, of Copenhagen, and at other continental stations.

Although the Permian species of Coelacanth, Coelacanthus granulatus, has been known since 1829, and although many authors have described specimens of it, it has remained unfortunately one of the lesser known of all Coelacanths. Since C. granulatus is the genotype of Coelacanthus, and since all the Carboniferous and some Triassic species have been assigned to this genus, it is surprising that further description has not been forthcoming. One of us (J. A. M. T.) has for some time been working on the Carboniferous Coelacanths, and it has been impossible to determine whether these really belong to the genus Coelacanthus. Accordingly it was hoped that by re-examining all the available material a more diagnostic description might be given. In doing this the authors have only been partly successful, as some of the most important generic characters—the dermal bones of the cheek and snout—were not preserved in any of the material examined. However, sufficient diagnostic characters have been provided by this research to distinguish the Carboniferous forms from this Permian genus.

In collaboration with Dr. R. G. S. Hudson, the author recently discussed the correlation of the Namurian and Dinantian strata of Western Europe (17) and reviewed the Variscan orogenic movements which attended their deposition (18). Only incidental reference, however, was made to the igneous activity of the periods under consideration and it is the purpose of the present communication to rectify this omission.

The periproctal plates of three specimens are here described and a comparison made with related genera, the latter including a description of the periproctals of Pseudodiscoidea.