中新世穿孔性貝類およびその生痕の化石 : 岐阜県瑞浪層群産

概要

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Nine species of rock-boring bivalves are obtained from the Miocene Mizunami group. They are Lithophaga (Leiosolenus) rechifora ITOIGAWA, Zirfaea subconstricta (YOKOYAMA) , Pholadidea sp., Parapholas minoensis ITOIGAWA, P. hiyoshiensis ITOIGAWA, Jouannetia (s.s.) cumingii (SOWERBY) Barbatia (Savignyarca) minoensis ITOIGAWA, Irus sp. and Pseudoirus sp., Their burrows which were filled with sands are also found as sandpipes. The number of fossil-occurring localities is eight and horizons are the Shukunohora sandstone member, the Akeyo formation and the Kubohara sandstone member. Substances into which they penetrated are basement rocks (mudstone), gravels of conglomerates and oysters. The sand-pipes are classified into nine types as type-I, -II, -III and -IV (burrows by primary boring), type-I' and II' (burrows by secondary boring), bifurcated and dilated sand-pipes (burrows by double boring) , and bowl-shaped sand-pipe (burrow of which upper part was cut off by erosion) based on their features. They are shown in Table 2. Woodboring "Teredo" and "Xylophaga" are noted and paleoecology of the fossil assemblage yielded from Shukunohora is discussed.
地学団体研究会の論文
1963-07-25