贵州南部中三叠世鱼鳞蛤组合序列

鱼鳞蛤(Daonella)是中三叠世双壳类特征性化石。它在世界上分布广泛、演化迅速,具有重要地层对比意义。这一属在我国分布于广西、贵州、云南、川南和藏南。滇、黔、桂三省交界地区,产鱼鳞蛤的中三叠世地层十分发育,在这里,鱼鳞蛤常常是地层划分的重要古生物依据。因此,研究鱼鳞蛤的种群分布规律是这一地区地质工作中的一项重要任务。笔者最近对黔南的鱼鳞蛤层进行了调查,发现有许多种在纵横分布上均十分稳定。

ASSEMBLAGES OF DAONELLA (BIVALVIA) IN SOUTH GUIZHOU PROVINCE

Six Daonella assemblages have been recognized in the Middle and lower Upper Triassic strata of South Guizhou.They are in ascending order as follows (1) Daonella guizhouensis assemblage of early Anisian;(2) D.americana D.producta D.ignolilis assemblage of middle to late Anisian;(3) D.pseudomoussoni-D.obtusa assemblage of latest Anisian to earliest Ladinian;(4)D.indica assemblage of early Ladinian;(5) D.jilongensis-D.lommeli assemblage of late Ladinian;(6) "Daonella" bifurcata-Halobia rugosoides assemblage of early Carnian.