. Bulletin of the British Museum (Natural History), Geology. 172 P. LEGRAND. Fig. 1 Outcrops of lower Palaeozoic in Algeria apart from the Intermediate Series (1); Intermediate Series and Cambro-Ordovician of the syneclise of Taoudeni (2); and Precambrian and Interme- diate Series (3). Upper member of sandstones with argillaceous silty intercalations. Fossils are only found near the base and include Diplograptus africanus Legrand, and G. (Glyptograptus) tariti Legrand and then, above, Diplograptus fezzanensis Desio. A lower Llandovery age was originally suggested for the whole Oued In Djerane
. Bulletin of the British Museum (Natural History), Geology. 172 P. LEGRAND. Fig. 1 Outcrops of lower Palaeozoic in Algeria apart from the Intermediate Series (1); Intermediate Series and Cambro-Ordovician of the syneclise of Taoudeni (2); and Precambrian and Interme- diate Series (3). Upper member of sandstones with argillaceous silty intercalations. Fossils are only found near the base and include Diplograptus africanus Legrand, and G. (Glyptograptus) tariti Legrand and then, above, Diplograptus fezzanensis Desio. A lower Llandovery age was originally suggested for the whole Oued In Djerane Formation (Legrand 1976, 1981, 1985a); then an Ordovician-Silurian boundary level at the top of the Diplograptus (?) kiliani Zone was proposed (Legrand 1985ft, 1986), but a further possibility, of a boundary at the top of the Middle member, must be considered. The arguments in favour of this last possibility are as follows: (i) A new subspecies very near to Diplograptus (?) kiliani is known in the Kurama Range, Usbekistan (but not in Kazakhstan) and it occurs, according to T. N. Koren, not below the Parakidograptus acuminatus Zone, as formerly believed, but below some beds where C. (Climacograptus?) extraordinarius or G. {Glyptograptus) persculptus was collected, (ii) On the other hand, C. (Climacograptus) incommodus has some affinities with C. (Climacograptus) extraordinarius and in this respect the position of Zygospiraella, a genus. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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