1 Pemberton S G, Frey R W. Quantitative methods in ichnology: Spatial distribution among populations. Lethaia, 1984, 17: 33-49？？
[2]
2 Droser M L, Bottjer D J. Ichnofabric of sandstones deposited in high-energy nearshore environments: Measurement and utilization. Palaios, 1989, 4: 598-604？？
[3]
3 Droser M L. Ichnofabric of the Paleozoic Skolithos ichnofacies and the nature and distribution of Skolithos piperock. Palaios, 1991, 6: 316-325？？
[4]
4 Droser M L, Bottjer D J. Trends and patterns of Phanerozoic ichnofabrics. Annu Rev Earth Planet Sci, 1993, 21: 205-225？？
[5]
5 Valentine J W, Collins A G, Meyer C P. Morphological complexity increase in metazoans. Paleobiology, 1994, 20: 131-142
[6]
6 McIlroy D, Logan G A. The impact of bioturbation on infaunal ecology and evolution during the Proterozoic-Cambrian transition. Palaios, 1999, 14: 58-72？？
[7]
7 Davies N S, Herringshaw L G, Raine R J. Controls on trace fossil diversity in an Early Cambrian epeiric sea: New perspectives from northwest Scotland. Lethaia, 2009, 42: 17-30？？
[8]
8 Harper D A T. The Ordovician biodiversification: Setting an agenda for marine life. Palaeogeogr Palaeoclimat Palaeocol, 2006, 232: 148-166？？
[9]
9 Palmer A R. The biomere problem: Evolution of an idea. J Paleontol, 1984, 58: 599-611
[10]
10 Sepkoski J J Jr, Miller A I. Evolutionary faunas and the distribution of Paleozoic benthic marine communities in space and time. In: Valentine J W, ed. Phanerozoic Diversity Patterns: Profiles in Macroevolution. Princeton and New York: Princeton University Press, 1985. 153-180？？
[11]
11 Sepkoski J J Jr. Ten years in the library: New data confirm paleontological patterns. Paleobiology, 1993, 19: 43-51
[12]
12 Rowland S M, Shapiro R S. Reef patterns and environmental influences in the Cambrian and earliest Ordovician. In: Kiessling W, Flügel E, Golonka J, eds. Phanerozoic Reef Patterns. SEPM Spe Publ, 2002, 72: 95-128
[13]
13 Liu J. Marine sedimentary response to the Great Ordovician Biodiversification Event: Examples from North China and South China. Paleontol Res, 2009, 13: 9-21？？
27 Webby B D, Cooper R A, Bergstrom S M, et al. Stratigraphic framework and time slices. In: Webby B D, Paris F, Droser M L, et al, eds. The Great Ordovician Biodiversification Event. The Critical Moments and Perspectives in Earth History and Paleobiology. New York: Columbia University Press, 2004. 41-47
32 Emilio R, Mariano M, Jordi M G, et al. Stratigraphy and sedimentology of the Middle Ordovician Hawaz Formation (Murzuq Basin, Libya). AAPG Bull, 2006, 90: 1309-1336？？
[26]
33 Davies N S, Ivan J S, Guillermo L, et al. Ichnology, palaeoecology and taphonomy of a Gondwanan early vertebrate habitat: Insights from the Ordovician Anzaldo Formation, Bolivia. Palaeogeogr Palaeoclimat Palaeocol, 2007, 249: 18-35？？
[27]
14 Gaffin S. Ridge volume dependence on seafloor generation rate and inversion using long term sea level change. Am J Sci, 1987, 287: 596-611？？
[28]
15 Berner R A. The rise of trees and how they changed Paleozoic atmospheric CO2, climate and geology. In: Ehleringer J R, Cerling T E, Dearing M D, eds. A History of Atmospheric CO2 and Its Effects on Plants, Animals and Ecosystems. New York: Springer, 2005. 1-7？？
[29]
16 Haq B U, Schutter S R. A chronology of Paleozoic sea-level changes. Science, 2008, 322: 64-68？？
[30]
17 Barnes C R. Ordovician oceans and climate. In: Webby B D, Paris F, Droser M L, et al, eds. The Great Ordovician Biodiversification Event. New York: Columbia University Press, 2004. 72-76？？
[31]
18 Miller A I. The Ordovician radiation: Toward a new global synthesis. In: Webby B D, Paris F, Droser M L, et al, eds. The Great Ordovician Biodiversification Event. New York: Columbia University Press, 2004. 380-388
[32]
19 Desjardins R P, Mangano M G, Buatois L A, et al. Skolithos piperock and associated ichnofabrics from the southern Rocky Mountains, Canada: Colonization trends and environmental controls in an early Cambrian sand-sheet complex. Lethaia, 2010, 43: 507-528？？
[33]
20 McIlroy D, Garton M. Realistic interpretation of ichnofabrics and palaeoecology of the pipe-rock biotope. Lethaia, 2010, 43: 420-426
