In Siberia Vendian is equated with a Yudoma Complex or Yudomian. Yudomian deposits of the Siberian Platform and adjacent geosynclines differ greatly in facies and thickness. According to the composition and structure of Yudomian deposits, four facies provinces may be recognized on the platform. Local stratigraphic charts for each province are presented and their correlation and possibility to subdivide the Vendian System in Siberia into three horizons or stages are substantiated. The upper stage (Nemakit–Daldyn), on the basis of palaeontological evidence, is in its turn subdivided into two zones: Anabarites trisulcatus and Purella antiqua.

The most important Early Baikalian rearrangement is proved to take place around 800±50 Ma. The pre-Vendian (Late Baikalian) movements, though less intensive, make the determination of the Yudomian lower boundary easier.

The specific character of Vendian biostratigraphy is discussed involving all groups of the organic remains, that causes the necessity of recognition, subdivision and correlation on the basis of the whole complex of data.

The boundary between the Vendian System and the Lower Cambrian Tommotian Stage (in type section) is proved to conform to the base of the Pestrozvet Formation, which divides the A. sunnaginicus and P. antiqua zones.

The Vendian in a stratotype area in the western part of the East European Platform includes three regional stratigraphic subdivisions: the Vilchanian, Volynian and Valdaian series, which clearly differ in structure and lithology. They are closely interconnected stratigraphically and geochronologically, and form an indivisible Late Baikalian structural stage of the platform sedimentary cover. The upper subdivision, the Valdaian Series, is palaeontologically substantiated and divided into horizons. The Vendian in such a composition has definite boundaries: the upper biostratigraphic, and lower lithostratigraphic ones, and is well correlated with the formations of the same age from other regions.

The present paper serves as a review on the stratigraphy and lithological characteristics of the Cambrian–Vendian boundary beds in the northwestern part of the East European Platform. This transition interval is represented by clastic rocks accumulated in humid climatic conditions. According to the lithological and palaeontological data the corresponding (transition) interval comprises two regional series: the Valdai Regional Series and the Baltic one. They both are divided into two regional stages (from below to top): Redkino, Kotlin, Rovno and Lontova.

The Redkino–Kotlin and Kotlin–Rovno boundaries are characterized by distinct contacts reflecting various changes in the sedimentary environment whereas the boundary between the Rovno and Lontova regional stages drawn on the basis of the palaeontological data only falls within the interval of continuous sedimentation.

Proceeding from the study of the fossil distribution and their living conditions during late Vendian and early Cambrian on the East European Platform the lower boundary of the Cambrian is most likely situated at the base of the Baltic Series.

In the Lublin area of the East European Platform (southeast Poland) sedimentation of the Vendian–Cambrian marine sequence began in Late Vendian times. Vendian and Cambrian strata occur in sedimentary continuity and their features indicate sedimentation in the tidal zone of a shallow epicontinental sea. The Vendian–Cambrian boundary, drawn on the basis of mainly palaeontological data, passes between the Vendotaenia and Sabellidites zones.

The principal characters of the biota from Upper Precambrian–Lower Cambrian rocks in the northwest of Argentina are described. It is possible to observe two groups: the trace fossils and the medusoid impressions. At the same time, a regional palaeogeographical analysis is attempted as well as a comparison with outcrops of similar age from the Gondwanaland area and from North America.

In the Early Cambrian, there were two peaks of the increase in number of new archaeocyathan genera. These diversification bursts are, perhaps, related to significant changes in Early Cambrian palaeogeography. The first burst at the beginning of the Atdabanian was, perhaps, connected with the initiation of archaeocyathan expansion beyond the Siberian Platform. During the second half of the Atdabanian, closely related archaeocyathan assemblages were established from North Africa to Australia because neither climate, nor geographic isolation could have affected their differentiation in that time. At the end of the Atdabanian and the beginning of the Botomian the number of archaeocyathan genera again increased sharply, and isolated provinces were established. The American–Koryakiyan province was formed in western North America (from Alaska to Sonora) and included the Koryakiya, while the Afro–Siberian–Antarctic province probably extended from North Africa and Western Europe to Siberia, Australia, and Antarctica. The main difference between the regular archaeocyathan assemblages lies in what skeletal elements filled the intervallum. There was a certain stability in the distribution of skeletal elements of high taxonomic rank and an interchangeability of elements of low taxonomic rank.

A stage subdivision of the Cambrian System is proposed. In the lower series four stages are distinguished (the Tommotian, Atdabanian, Botomian, Tojohnian); in the middle series, two (the Amga and Maya stages); in the upper series, three (the Ayusakkanian, Sakian, and Aksayan stages). The stratotypes of the stages of the lower and middle series are located on the Siberian Platform, while the stratotypes of the stages of the upper series are found in Kazakhstan (the Maly Karatau). The lower boundary of the Cambrian is drawn along the bottom of the Al. sunnaginicus Zone, the lower boundary of the middle series along the Schistocephalus Zone, and that of the upper series along the Cormagnostus simplex Zone. The Cambrian–Ordovician boundary is not quite clear yet, but it is most likely to be drawn along the bottom of the C. proavus Zone.

Interactive digital processing of multispectral satellite images (Landsat MSS) using principal components transformations and spatial filtering has clarified the position of continuous sutures linking apparently isolated Pan African (late Proterozoic) ophiolites. These have been field-checked and an arrangement of Pan African suture zones is proposed. Spatial filtering has also highlighted faults with various trends which can be related to the late Precambrian tectonics of the Horn of Africa region.

The Northern Suture is a fault separating the Cretaceous Kohistan island arc terrain (northwest Himalayas) from Palaeozoic sediments of the Asian Plate to the north. The Kohistan arc includes volcanic and sedimentary rocks (andesitic lavas, tuffs, volcaniclastics, slates and limestones), metamorphosed to greenschist facies and intruded by the two-phase Kohistan Batholith. Asian continental margin sediments are mainly of shelf type, are variably metamorphosed and intruded by the Karakoram Batholith. The Northern Suture is a zone of melange from 150 m to 4 km wide, and contains blocks of volcanic greenstone, limestone, red shale, conglomerate, quartzite and serpentinite in a slate matrix. It has a strong planar fabric; but in many places bedding is preserved in blocks and matrix, and depositional rather than tectonic contacts are seen between the two. The melange is inferred to be an olistostrome largely derived from the Kohistan arc, formed in a small back-arc basin between Kohistan and Asia. Limestone blocks in the melange are dated as Aptian–Albian; post-tectonic intrusions yield radiometric ages from 111 to 62 Ma. The Northern Suture therefore probably formed in the early Late Cretaceous during closure of the back-arc basin. The Tethys ocean lay south of Kohistan, where the Main Mantle Thrust represents the westward continuation of the Indus–Tsangpo Suture.

Facies descriptions and environmental interpretations are given for outstanding sections of marine Tithonian to Hauterivian strata in the High Cordillera of the central Chilean Andes. Comparisons are made with correlative strata in other regions in Chile, and with the Neuquén Basin of west central Argentina. The rich and partly endemic bivalve fauna, which has strong African affinities, shows no change up the stratigrapic sequence that cannot be related to local facies. Water depth is recognized as the main variable controlling the distribution of the bivalve and ammonite faunas. Utilizing data from both Chile and Argentina, a model is put forward for the late Jurassic to mid Cretaceous sequence whereby the facies distributions are accounted for by the interaction of global sea-level changes and regional tectonics in a shallow back-arc basin.

Trilobites from the Soom Shale, Cedarberg Formation, of the Table Mountain Group, South Africa, have been identified as Mucronaspis olini Temple, indicating a latest Ordovician (Rawtheyan–Hirnantian) age. This new data is taken as an opportunity to present new records of some non age-diagnostic brachiopods and molluscs from the area, and also to review the substantial shelly fauna from the overlying Disa Member of the Cedarberg Formation. It is concluded that that fauna is of Hirnantian age and not early Llandovery as stated by some previous authors.

The first occurrence of Early Paleozoic land plants is reported from South Africa. The plant remains are small, compact tetrahedral spore tetrads. They occur abundantly in the Soom Shale Member of the Cedarberg Formation, Table Mountain Group. Marine? phytoplankton (sphaeromorphs or leiospheres) occur with the spore tetrads in all samples. Rare chitinozoans are found in half the samples. Together with similar spore tetrads from the Paraná Basin (Gray et al. 1985) these are the first well-documented records of Ashgill and/or earlier Llandovery land plants from the Malvinokaffric Realm, and from the African continent south of Libya. These spore tetrads have botanical, evolutionary, and biogeographic significance. Their size in comparison with spore tetrads from stratigraphic sections throughout eastern North America, suggests that an earliest Llandovery age is more probable for the Soom Shale Member, although a latest Ordovician age cannot be discounted. The age of the brachiopods in the overlying Disa Siltstone Member has been in contention for over a decade. Both Ashgillian and Early Llandovery ages have been proposed. The age of the underlying Soom Shale Member based on plant spores and trilobites (earliest Llandovery or latest Ashgillian) suggests that the Disa Siltstone Member is also likely to be of Early Llandovery age, although the distance between the Soom Shale Member spore-bearing locality and rocks to the south yielding abundant invertebrate body fossils at one locality is great enough to permit diachroneity.