Why do we find large "pools" of fossil plants and animals but none of recent origin? Actuallysuch concentrations are found today when natural disasters occur, but our minds remain on the disasters and forget the numerous dead. The volcanic eruption of Vesuvius in 79 AD killed manypeople in the ancient Roman cities of Herculaneum and Pompeii where we may still see some of their remains. Every flood kills and buries thousands of animals; a sudden flood entering a saltwater cove, or sheltered inlet, will bury and kill literally millions of seashore living things, perhaps not to be seen again until dug up as fossil during some distant millennium. What may seem like a common occurrence in the fossil-filled rocks exposed to our eyes, is a seriesof scattered events from a past millions upon millions of years long.
为什么我们发现大量动植物的化石，却没有一种是较为近期形成的？实际上，在今天，自然灾害发生时，也有类似的生物的集体死亡，只是我们专注于灾害本身，忘却了众多消亡的生物。公元79年，维苏威火山爆发，使古罗马的赫尔库拉内姆和庞培两个城市许多人丧命。在那儿，我们仍能看到其中一些遗骸。每次洪水都摧毁并埋葬掉成千上万的动物。一场突然泛滥的洪水，涌进一个咸水小海湾或隐蔽的小湾，会葬送掉海岸边数以百万计的生命。这些生命可能要经过几千年漫长的岁月，成为化石被挖掘出来之后，才能重见天日。人们所能看到的布满化石的岩石，看似寻常，却是千百万年来断断续续发生的一系列事件演变的结果。