Janet: "Ignatius Donnelly stands out as one early expositor of an alternative view of antiquity. Early in life he served as Lieutenant Governor of Minnesota and subsequently as a Congressman from that state. Later on, in 1882, he authored the book, "Atlantis and the Antedeluvian World", and the following year he produced "Ragnarok: The Age of Fire and Gravel". Here he took issue with the then developing ice-age theory, tracing the residues in question instead to the impact of a comet in the relatively recent past. "
I believe that the problem lies in the following: Uniformitarian view cannot incorporate comets and other catastrophes. That is incorrect. The difference between the two views is imo that catastrophism relies on catastrophies to be the main (or only) way changes take place. While noone can deny that volcanoes, comets, asteroids, earthquakes and floods happened, the data show that they are relatively small scale and time. An occasional hit by an asteroid, an occasional earthquake does not explain the majority of features observed.
Looked upon today in the context of modern science, the principle of uniformity means simply that all phenomena of geology must be explained through the laws of science we accept as valid. The fundamental laws of physics, chemistry and biology must have applied uniformly from early pre-cambrian time to the present. No explanation f an event that occurred in the Cambrian period or the Triassic period can be considered acceptable if it violates a scientific law we apply today. Supernatural forces are ruled out of the physical explanation of deposition and deformation of strata."
"The principle of uniformity does not, however, require that the intensity of each geological process shall have been uniform throughout all time. To the contrary, we accepts as a valid conlusion that the deformation of strata and intrusions of plutons may have been more intense at one point in time or another... There are some good reasons to suppose that the overall total intensity of igneous and tectonic activity has been declining since early Precambrian time...."