This paper deals with the study of beryl, its variety, petrographic, and gemological specifications in Bahr-e-Abad area Jalalabad city. Beryl is a relatively rare silicate mineral, cyclo-silicate, chemical composition Be3Al2 (Si6O18) hexagonal crystal shape. It found igneous metamorphic rocks many parts world. In order to achieve aim this paper, three methods, namely; library work, fieldwork, l...

An enrolled exoskeleton of the holaspid specimen of a tiny agnostid Peronopsis integra (BEYRICH, 1845) entombed inside a conch of the hyolithid ?Buchavalites sp. is described from the middle Cambrian (Drumian) Jince Formation of the Příbram-Jince Basin (Czech Republic). The agnostid is associated with an ichnofossil of the feeding trace classified as Arachnostega-type behaviour. The enrolled at...

Almost all of the modern animal phyla appear to originate in a relatively compressed interval of time known as the Cambrian Explosion. Although several factors have been identified that may have enabled the Cambrian Explosion, there remains the question of the final trigger. The development of cellular differentiation, the capacity of a cellular lineage to become specialized permanently in resp...

The discovery of fossilized brains and ventral nerve cords in lower and mid-Cambrian arthropods has led to crucial insights about the evolution of their central nervous system, the segmental identity of head appendages and the early evolution of eyes and their underlying visual systems. Fundamental ground patterns of lower Cambrian arthropod brains and nervous systems correspond to the ground p...

The Middle Member of the Lower Cambrian Deep Spring Formation at Mount Dunfee, Nevada contains a diverse assemblage of stromatolites that formed on a tideand storm-dominated, siliciclastic-influenced, carbonate shelf. The stromatolites formed in a shallow subtidal environment within and near active oolite shoals under strongly focused currents. The stromatolites occur in four different lithofac...

Fossils of the sponge Angulosuspongia sinensis from calcareous mudstones of the middle and upper part of the Kaili Formation (Cambrian Stage 5) in the Jianhe area of Guizhou province, South China, exhibit an apparently reticulate pattern, characteristic of the Vauxiidae. Energy Dispersive X-Ray Spectrometry (EDS) and Raman spectroscopy analysis indicate the presence of silica in the skeletal el...

The evolutionary divergence of cnidarian and bilaterian lineages from their remote metazoan ancestor occurred at an unknown depth in time before the Cambrian, since crown group representatives of each are found in Lower Cambrian fossil assemblages. We report here a variety of putative embryonic, larval, and adult microfossils deriving from Precambrian phosphorite deposits of Southwest China, wh...

Beautifully preserved organisms from the Lower Cambrian Maotianshan Shale in central Yunnan, southern China, document the sudden appearance of diverse metazoan body plans at phylum or subphylum levels, which were either short-lived or have continued to the present day. These 530 million year old fossil representatives of living animal groups provide us with unique insight into the foundations o...

The rapid appearance of bilaterian clades at the beginning of the Phanerozoic is one of the most intriguing topics in macroevolution. However, the complex feedbacks between diversification and ecological interactions are still poorly understood. Here, we show that a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran-Cambrian transition indicates that body-plan div...

Echinoderms are unique in being pentaradiate, having diverged from the ancestral bilaterian body plan more radically than any other animal phylum. This transformation arises during ontogeny, as echinoderm larvae are initially bilateral, then pass through an asymmetric phase, before giving rise to the pentaradiate adult. Many fossil echinoderms are radial and a few are asymmetric, but until now ...