Verification for the homogeneity of fossil assemblages within the same environment.

虽然以前认为同一环境中的本地化石组合由于时间平均过程而均匀化，但很少有人证实这一点。以日本东南太平洋侧高知县东部上新世阿南奈组内陆架相粉砂化石25种979个标本为基础，定量比较了3个化石点（1、2、3）的物种组成。(1)各生境的优势种均为角蝇，其次为褐飞燕，第三为黄颡鱼（Fulvia mutica），第四为异花蚜（Acila divaricata）。(2)在第1和第2个地点，第5优势种为日本斑蝶（Oblimopa japonica），而第3个地点的第5优势种为异斑蝶（Gari anomalala）。(3)在第1和第2个地点，沙蚤是第6优势种，而在第3个地点，帕菲亚是第6优势种，因此，第1和第2个地点的物种组成几乎是均匀的，而第3个残余地点在次要物种组成上是不同的。

Although an autochtonous fossil assemblage within the same environment has been previously considered to be homogenized due to a time-average process, few has verified it. The species compositions among the three fossil localities (localities 1,2, and 3) are quantitatively compared based on the 979 specimens of twenty-five species in fossilferous silty sands of the inner-shelf facies of the Pliocene Ananai Formation, eastern part of Kochi Prefecture, Pacific-side of southeastern Japan. The three localities are arranged in the same horizon within the 180m distance(1) The most dominant species is Angulus vestarioides in all the localities, the second Nassarius caeratus, the third Fulvia mutica, and the fourth Acila divaricata.(2) In the localities 1 and 2, the fifth dominant species is Oblimopa japonica, whereas Gari anomala is the fifth dominant species in the locality 3.(3) Ammusiopenten praesignis is the sixth dominant species in the localities 1 and 2, but in loclity 3, Paphia sp.is.As a result, the species compositions of the localities 1 and 2 are considered to be nearly homogenized, whereas the remnant locality 3 is considered to be different in the minor species composition.