Given these factors, some areas have become a treasury of well-preserved ichthyosaur fossils.The deposits at Holzmaden, Germany, present an interesting case for analysis.

• 但是它 们的石化需要一系列因素：软组织的腐烂速度缓慢，很少被其他动物残食，缺少混杂、冲走 小骨头的快速水流和波浪，以及相当快地被掩埋。