摘要
20180197 Wang Qi （School of Earth Science and Resources, Chang＇an University, Xi＇an 710054, China） ; kiu Yunhuan Research on the Tubular Fossils of the Early Cambrian Xixiang Biota in Southern Shaanxi Province, NW China （Acta Micropalaeontologica Sinica, ISSN1000-0674, CN32-1189/Q, 34（1）, 2017, p. 49-60, 4 illus. , 57 refs. ） Key words： Cambrian, biocenoses, fossils, Shaanxi Province The Xixiang biota has a great amount of tubular fossils. This paper summarizes and describes three major types of them, including hyoliths, hyolithelminths and anabaritids. The hyoliths in this biota belong mainly to Circo- thecida and are considered as the first stage of Cambrian hyoliths evolution. These hyoliths have different kinds of skeletal structures, which could be divided into unilaminar shells and multilayered shells. The multilayered shells could also be divided into concentric kind and eccentric kind. The unilaminar shells and the concentric multilayered shells are likely to be native, and the eccentric multilayered shells are likely to be diagenetic.
