Between Hutton's day and Lyell's there arose a new geological controversy, which largely superseded, but is often confused with, the old Neptunian-Plutonian dispute. The new battle became an argument between catastrophism and uniformitarianism—unattractive terms for an important and very long-running dispute.

在赫顿时代和莱尔时代之间，地质学界发生了一场新的争论。它在很大程度上取代了过去的水成论与火成论之争，而又往往交混在一起。新的战斗成为灾变论和均变论之争。给一场重要而又旷日持久的争论起这样的名字，似乎有点儿不够味儿。

Catastrophists, as you might expect from the name, believed that the Earth was shaped by abrupt cataclysmic events—floods principally, which is why catastrophism and neptunism are often wrongly bundled together. Catastrophism was particularly comforting to clerics like Buckland because it allowed them to incorporate the biblical flood of Noah into serious scientific discussions. Uniformitarians by contrast believed that changes on Earth were gradual and that nearly all Earth processes happened slowly, over immense spans of time. Hutton was much more the father of the notion than Lyell, but it was Lyell most people read, and so he became in most people's minds, then and now, the father of modern geological thought.

灾变论者——顾名思义——认为，地球是由突发的灾难性事件形成的——主要是洪水。这就是人们常常把灾变论和水成论互相混淆的原因。灾变论尤其迎合巴克兰这样的教士的心理，这样他们可以把《圣经》里诺亚时代的洪水纳入严肃的科学讨论。均变论者恰恰相反，认为地球上的变化是逐渐形成的，几乎所有的地质变化过程都是缓慢的，都要经历漫长的时间。最先提出这种见解的与其说是莱尔，不如说是赫顿，但大多数人读的是莱尔的作品，因此在大多数人的脑海里，无论是当时还是现在，他成了近代地质学之父。

Lyell believed that the Earth's shifts were uniform and steady—that everything that had ever happened in the past could be explained by events still going on today. Lyell and his adherents didn't just disdain catastrophism, they detested it. Catastrophists believed that extinctions were part of a series in which animals were repeatedly wiped out and replaced with new sets—a belief that the naturalist T. H. Huxley mockingly likened to "a succession of rubbers of whist, at the end of which the players upset the table and called for a new pack." It was too convenient a way to explain the unknown. "Never was there a dogma more calculated to foster indolence, and to blunt the keen edge of curiosity," sniffed Lyell.

莱尔认为，地球的变迁是一贯的，缓慢的--过去已经发生过的一切都可以用今天仍在发生的事情来解释。莱尔和他的信徒们不但瞧不起灾变论，而且对它深恶痛绝。灾变论者认为，绝种是一系列过程的组成部分，在此过程中，动物不断灭亡，被新的动物取而代之--博物学家T.H.赫胥黎把这种看法挖苦地比做是"惠斯特牌戏里的一连串胜局，到了最后，打牌的人推翻桌子，要求换一副新牌"。以这种方法来解释未知的事物未免过于俗套。“从来没有见过比这样的一种教条更蓄意助长懒汉精神，更削弱人们的好奇心的了。”莱尔嗤之以鼻地说。