. Bulletins of American paleontology. Silurian Radiolation Zonation. West Texas: Noble 15. Text-figure 7 Kazakhstan. -Correlation of local radiolarian zones in the Marathon uplift with radiolanan assemblages described from Japan and McKerrow, likely. 1990), so both possibilities are equally Japan By far, the most extensive work on Silurian radio- larians appears in studies by Wakamatsu et al. (1990) and Furutani (1990) from two regions in Japan. Ra- diolarians have been recovered from measured sec- tions of partially dismembered siliceous and tuffaceous shale sequences from the Kurosegawa Tect
. Bulletins of American paleontology. Silurian Radiolation Zonation. West Texas: Noble 15. Text-figure 7 Kazakhstan. -Correlation of local radiolarian zones in the Marathon uplift with radiolanan assemblages described from Japan and McKerrow, likely. 1990), so both possibilities are equally Japan By far, the most extensive work on Silurian radio- larians appears in studies by Wakamatsu et al. (1990) and Furutani (1990) from two regions in Japan. Ra- diolarians have been recovered from measured sec- tions of partially dismembered siliceous and tuffaceous shale sequences from the Kurosegawa Tectonic Zone (Wakamatsu et al., 1990) in southwestern Japan, and from the Fukuji Area, Gifu Prefecture, central Japan (Furutani, 1990). Local radiolarian assemblages were described for each region and are discussed below. Kurosegawa Tectonic Zone Four distinct assemblages described by Wakamatsu et al. (1990) are interpreted to be of Silurian age. Struc- tural dismemberment of the Kurosegawa sections and poor chronostratigraphic control have made the strati- graphic relationships between assemblages difficult to interpret. The Devoniglansus unicus assemblage has been interpreted to be younger than the Pseudospon- gopmmim sagittatum assemblage (Wakamatsu et al., 1990), yet comparison with the stratigraphically intact assemblages of the Marathon uplift indicates that the P. sagittatum assemblage may be younger than D. un- icus assemblage (Text-figure 7). A description of the four assemblages and correlation to the Marathon bio- zones follows. Assemblage 1. Secuicollacta .' exquisita .Assem- blage. —This assemblage is poorly preserved and only a few taxa are described, none of which are particularly diagnostic. It contains Secuicollacta Waka- matsu et al., 1990, a poorly preserved rotasphaerid with 10 or more rod-shaped primary spines and rem- nants of secondary spines, and a specimen of Good- bodium. Based on the presence of Secuicollacta, this assemblage occurs within t
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