“…In contrast to the Carboniferous stratigraphic scale, for which a detailed succession of ammonoid genozones and, for some intervals, of the species zones has been developed, zonal stratigraphy is neither substantiated nor accepted for the Permian." Table 12.3 Principal regions important for Permian ammonoid biostratigraphy with selected articles and ammonoid monographs Arctic Canada Nassichuk et al 1965, Nassichuk 1970, 1977 Texas and North Mexico Plummer and Scott 1937, Miller and Furnish 1940a, King and Miller 1944, Spinosa et al 1975 Sicily Gemmellaro 1887, 1888 Crimea Toumansky 1931 Ruzhencev 1951, 1952, Bogoslovskaya 1962Verkhoyan Andrianov 1966, 1985 Pamirs (Tajikistan) Toumansky 1963, Ruzhencev 1978, Leonova and Dmitriev 1989, Leven et al 1992 South China Zhao and Zheng 1977, Zhao et al 1978, Liang 1981, Zhou 1987b, a, Sheng 1988Transcaucasus Ruzhencev 1959, Shevyrev 1965, Teichert et al 1973, Ghaderi et al 2014 Central Iran Bando 1979Timor Haniel 1915, Smith 1927, Gerth 1950 Western Australia Glenister and Furnish 1961 Fig. 12.9 Correlation of ammonoid zonations of the Permian, after Leonova (2011), Bogoslovskaya et al (1999) and Jin et al (1997) In total, only a maximum of about 20 units defined by ammonoids can be separated; a zonation for the Middle Permian (Guadalupian) stages has not been established (Figs.…”