The Lower Carboniferous blastoid Astrocrinus tetragonus Austin and Austin from Grassington, Yorkshire, and the validity of Astrocrinus benniei Etheridge

Despite surviving longer than any other blastozoans, blastoids were exceptionally conservative in their morphology and usually symmetrically pentaradiate. Astrocrinus is a rare exception that lacked a stem and some thecal plates, although differing interpretations of its morphology and taxonomy have been published. Astrocrinus had a flattened, tetralobate theca covered in minute spines, and with a plane of symmetry through the AB interray and the D ray. Four ambulacra are long, thin, and curved down deep sinuses between the thecal lobes to reach the basal surface. The D ambulacrum is short, broad and horizontal. Astrocrinus tetragonus was first described from the Carboniferous Limestone of Settle, Yorkshire. Here it is recorded for the first time from the Brigantian, near Grassington. The new specimens confirm that A. tetragonus had a single basal plate which is kite- shaped, entirely surrounded by four radials and separated from the D ray radial. Astrocrinus benniei was described from the Scottish Brigantian and its basal plate is elongate pentagonal with a short common suture with the D ray radial. Astrocrinus occurs in the Irish Asbian and Brigantian. To date, only A. tetragonus can be confirmed from Ireland.

Coprolites in an Early Carboniferous microvertebrate fauna from Derbyshire, UK

Formic acid treatment of bioclastic limestones, and the disaggregation of impersistent black marl samples using the kerosene and boiling water method has yielded a very rich microvertebrate fauna from the Early Carboniferous Eyam Limestone Formation (Peak Limestone Group, Carboniferous Limestone Supergroup) of Derbyshire (UK). Small numbers of vertebrate coprolites were found in the picked residues, some of which are described here as Vinculostercus vermiformis ichnogen. et ichnosp. nov. The low diversity coprofauna also includes Eucoprus sp., and two otherwise unidentified ichnogenera.

GOLD-JASPEROID MINERALIZATION IN ZONE OF THE SHARTYMSKIY FAULT (SOUTH URALS)

The Shartymskiy Graben was formed at zone of the Shartymskiy Fault in the late collision stage of development of the Southern Urals on the joint of the Western and Eastern Magnitogorsk sub-zone in conditions of variable compression and stretching, and was made with the Lower Carboniferous limestone. Occurrences of gold-bearing metasomatites (jasperoids, sericite-chlorite-carbonate-quartz, sericite-quartz) have been established in the precontact zones of carbonates, gabbro-dolerites, diorites dykes, and small intrusions of sub-alkaline leuсograniteporphirs of the Shartymskiy massif. Mediated connection with them of gold sprouts is established. The gold economic concentration of the Vorontsovskiy deposit type is expected on the certain sections of metasomatites of jasperoid association and their weathering crust.

New views about the Sizim suite (Lower Permian, the Polar Urals)

The article for the first time presents data on the material composition and structure of the Sezym Formation of the Lower Permian of the Western slope of the Polar Urals, which lies with stratigraphic disagreement on shallow medium-Carboniferous limestone and according to the overlapping deep-sea Artinian terrigenous deposits. New data are important for paleogeography and geodynamic reconstruction of the North-East of the European platform in the late Paleozoic.