峡东震旦系陡山沱组宏体生物群*

描述了陡山沱组宏体化石11属11种(其中5新属,5新种).这一发现表明,多细咆后生动、植物在震旦纪陡山沱期已经繁荣.在后生动物中,除有大量软躯体动物外,具有内、外骨骼的动物已有少量出现,这是生命发展史上的重大事件.有的属种,有着复杂化的内部器官,或许代表着一个生物进化方向.在后生植物中,高级藻类已显示出初步的形态分化,在生态系中起了重要作用.它们排挤或取代了几乎与地球历史同样悠久的微生物群落.

MACROFOSSIL BIOTA FROM UPPER SINIAN DOUSHANTUO FORMATION IN EASTERN YANGTZE GORGES, CHINA

The Sinian section in eastern Yangtze Gorges established by Lee and Chao (1929) has ever sirlce been considered as the stratotype for the contemporaneous strata in China. It can be a potential candidate for a global stratotype section to be established as a new geological system because of its high quality studies not only in sequence, fossils, contact relations, mineral resources and palaeogeographical environments but also in palaeomagnetism, oxygen-carbon stable isotope ratio, and isotopic dating. Here the Sinian System consists of the Liantuo, Nantuo, Doushantuo and Dengying Formations in ascending order (Text-fig. l), unconformably underlain by granite or metamorphosed rocks and conformably overlain by the earliest Cambrian beds bearing small shelly fossils.