Variation and natural selection would also afford a key to a multitude of geological facts otherwise wholly unaccounted for, as, for example, why the… - Charles Lyell

By the multiplying of slight modifications in the course of thousands of generations, and by the handing down of the newly-acquired peculiarities by inheritance, a greater and greater divergence from the original standard is supposed to be effected, until what may be called a new species, or, in a greater lapse of time, a new genus, will be the result.

He [ Aristotle ] refers to many examples of changes now constantly going on, and insists emphatically on the great results which they must produce in the lapse of ages. He instances particular cases of lakes that had dried up, and deserts that had at length become watered by rivers and fertilized. He points to the growth of the Nilotic delta since the time of Homer, to the shallowing of the Palus Maeotis within sixty years from his own time... He alludes, ...to the upheaving of one of the Eolian islands, previous to a volcanic eruption. The changes of the earth, he says, are so slow in comparison to the duration of our lives, that they are overlooked; and the migrations of people after great catastrophes, and their removal to other regions, cause the event to be forgotten. ...He says [twelfth chapter of his Meteorics] 'the distribution of land and sea in particular regions does not endure throughout all time, but it becomes sea in those parts where it was land, and again it becomes land where it was sea, and there is reason for thinking that these changes take place according to a certain system, and within a certain period.' The concluding observation is as follows: 'As time never fails, and the universe is eternal, neither the Tanais, nor the Nile, can have flowed for ever. The places where they rise were once dry, and there is a limit to their operations, but there is none to time. So also of all other rivers; they spring up and they perish; and the sea also continually deserts some lands and invades others The same tracts, therefore, of the earth are not some always sea, and others always continents, but every thing changes in the course of time.'

In my account of his [Lamarck's] theory, I did not, at the time, fully appreciate the deep conviction which it displays of the slow manner in which geological changes have taken place, and the insignificance of thirty or forty centuries in the history of a species, and that, too, at a period when very narrow views were entertained of the extent of past time by most of the ablest geologists, and when great revolutions of the earth's crust, and its inhabitants, were generally attributed to sudden and violent catastrophes.