Microfossil

...For example, in terms of origin, they are classified into (1) layered sedimentary structures (stromatolites) created by seaweed and bacteria by solidifying sediment particles with calcite and silicic acid, sedimentary structures that have been left in the state they were stirred up by feeding behavior, and sedimentary structures of biological origin such as footprints, crawling tracks, burrows, and foraging behavior on the surface of soft sediments, (2) erosion structures caused by organisms drilling holes in solidified sediments, gnawing, biting, or scratching, and (3) feces, eggs, egg sacs, and stomach contents that indicate other life activities. Fossils that are small in size and can only be identified under a microscope are called microfossils. These include animals and plants with tiny shells and skeletons such as foraminifera, radiolaria, ostracodes, and diatoms, parts of the skeletons of large animals with complex structures (such as sea urchin spines and bone fragments), and plant pollen and spores. ...

*Some of the terminology that mentions "microfossil" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…例えば成因的には，(1)海藻やバクテリアなどが堆積物の粒子を方解石やケイ酸で固結させて作り上げた層状堆積構造(ストロマトライト)，採餌行動によりかくはんされた状態がそのままとどめられた堆積構造，軟らかい堆積物の表面に残された足跡･はい跡･巣穴･採餌行動の跡など生物起源の堆積構造，(2)固結した堆積物に対して穴をあけた跡，かじったり，かんだり，ひっかいたりした生物による侵食構造，(3)その他の生活活動を示す糞（ふん）･卵･卵囊･胃内容物などに分類される。　形態が小さく，顕微鏡下ではじめて識別されるような化石を微化石microfossilという。この中には，有孔虫･放散虫･貝形虫･ケイ藻のような微小な殻や骨格をもつ動植物，複雑な構造をもつ大型動物の骨格の一部分(例えばウニのとげや骨片など)や，植物の花粉･胞子などの化石が含まれる。…

※「microfossil」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報