These fossils are from lacustrine deposits and are well-preserved.

lacustrine 是由拉丁词根 lacus（意为"湖"）加上后缀 -strine 构成的形容词，表示"与湖泊有关的"或"湖相的"。在沉积学中，lacustrine deposits 特指由湖泊环境形成的沉积物。