(Table 4) Turronian-lower Campanian calcareous nannofossils of ODP Hole 121-755A

Species abundance: A = abundant (at least 1 specimen per field of view at 1500 X), C = common ( 2 specimen per 2-10 fields), F = few (1 specimen per 11-100 fields), R = rare (1...物种丰度（Species abundance）分级标准如下：A为丰富型（abundant），即1500倍放大视野下每视野至少1个标本；C为常见型（common），即每2-10个视野可见2个标本；F为稀少型（few），即每11-100个视野可见1个标本；R为稀有型（rare），原文未完整给出其判定标准