A couple questions,
1) Do you have some examples of when uniformitarianism has provided data to undermine evolutionism?
2) What do you believe happened to the dinosaurs? Did they go extinct prior to the ark?
1) There are a number of things with known (that is to say, observably consistent in relatively stable conditions) rates of decay; others have measures of accumulation. When faced with issues like these, evolutionaries (methodological, uniformitarian naturalists) often reach into their "black bag of unknown naturalistic explanations" to supply a solution. It doesn't matter if the solution has that much feasibility; it just needs to sound good enough to be a stopgap measure. Call it the "Atheism-of-the-gaps." The mechanics of the "solution" are invariably left completely unfilled-in, and if the best ideas run afoul of laws of physics, etc., no problem--these are just kinks to be ironed out. This kind of blind faith is OK, because it doesn't resort to an Outside Entity.
Examples: #1 Probability and Statistics as well-defined science. At one time, evolutionary origins had a vague back end. Millions of years sufficed to describe life on earth, and further millions could be added on (and were) to give whatever room was thought necessary. Big Bang cosmology has given the world vast increases of time from the first modern scientific proposals, but with the added inconvenience of a limiting factor, an omega point that virtually all admit eliminates eternal time and space. Truly atheistic evolution rejects ultimate teleology on principle, which eliminates the possibility on naturalistic grounds of directed "progress," design, or blueprint. This is what makes Intelligent Design a "heresy" of scientism, since it (only!) seeks to plug purpose into the evolutionary process, and that's not allowed.
Hence, the probability factors for accidental life--to say nothing of the complexity and variety--decisively dwarf both the unfathomable depth and breadth of the universe with its manifold contents, and the epochs of time provided. This has led to "sober" cosmologists publishing their convictions of the existence of the "multiverse": however many discrete universes it takes to bring about this 10^nth chance product in which we live, move, and have our being. Other proposals include an "oscillating" universe, in which the Big Bang reverses itself after so long, and starts over, infinitely. The laws of physics and chemistry, governed by one branch of mathematics after another, crush the probability of life-by-chance down to absolute zero.
#2 Comets. Comets are disintegrating; that's what we see by their "tail." There are multiple periodic comets known to astronomers, but in fact there shouldn't be any--if cosmic evolution is true--because they would have burned out eons ago. Unless... unlessssss (!) there must be a
seed-bed spitting them out now and then, to get caught in our Sun's gravity well and pulled in until they burn out. The "Oort Cloud" is a evolutionary best-guess as to why, on uniformitarian principles, there are comets. We'll have to find the cloud (someday), in order to determine all the curious things about how it exists, its principles of operation, etc. In other words, the Oort Cloud is a "Just-So" story from the evolutionaries about comets.
#3 Strata. Uniformitarian processes do not adequately explain earth strata, such as revealed famously in the Grand Canyon, etc. Evolutionists date various strata as successive ages, but offer no explanation as to why the strata are stacked in such planar layers, or how for instance progressive environments (lasting for ages) were characterized by predominance of one kind of rock or dust after another. Inversions ("older" layers on top of "younger" ones) and "missing" layers are also inexplicable on the presumption of extensive, pervasive, and long-lasting periods of static conditions presumed by uniformitarian a prioris.
#4 Erosion. Erosion is a constant process (and one that opposes ages-long stratification theory). It is possible to date (relatively) the origins of the Grand Canyon in much less time than standard evolutionary epochs wish for it, based on ordinary hydrographic analysis; and there is a significant lack of evidence of erosion at each layer boundary, and other significant anomalies. The Niagara river/falls/escarpment has presented further challenges to evolutionary claims, starting with the very first popularized survey by Charles Lyell conducted in 1841. The local estimate of erosion (simply based on imprecise lifetime gauges) was around 3ft. per annum. Lyell found the length of the gorge was approx. 35,000 ft.; and according to his need to discredit biblical chronology, he stipulated the actual erosion must be closer to 1ft. per annum; ergo the gorge was at least 35,000 years old.
The actual average estimate of erosion over a more restricted modern period is 5ft. per annum. Even allowing for fluctuations in the rate of erosion based on water volume, and varying hardness/composition of the strata, this figure yields a far smaller time scale for erosion of the Niagara gorge. Modern evolutionary thought, which incorporates a 12,000 yr old ice age, must still first increase and then greatly reduce the estimated rate of erosion in theoretical retrogression, just to make the evidence on hand fit with a time scale that has shortened Lyell's arbitrary guesswork (and dismissal of eyewitness testimony) by a factor of 4.
Here is illustrated in several ways the ad hoc nature of the original evolutionary challenge. Less than 200yrs ago biblical chronology needed "only" be undermined by a single exponential factor; a few thousand years was all evolution required to be "true," and God's Word to be relegated to fairy-tale status. Today, Lyell's bona fide fairy-tale thinking is a footnote, if that (the man is considered a great pioneer of science, I guess because everyone falsified his data back then?). There is hardly any appreciable difference (depending on the criteria) between Creationist/Flood interpretations of the actual Niagara data, and evolutionary interpretations of the same that acknowledge an ice age only a few thousand years ago.
There are other measures of decay that may be cited, such as the present decline in the earth's magnetic field. Reversed and increased on uniformitarian principles, the earth must have been waterless and uninhabitable (much) less than a bare 100,000 years ago, hardly cracking the present geological/zoological epoch. Has the magnetic field fluctuated, both increasing and decreasing over the ages (proposed evolutionary "fix")? What is the evidence for this? There isn't any; this or something like it is just required for evolution to be true. So, uniformitarianism is only good for when it can be postulated to support evolutionary ideas, and jettisoned as soon as it fails to supply a helpful condition.
The ultimate point is not for us to "transgress" into the data-driven realm of the scientists, and pretend to be experts in geology or other areas in which we have not done serious study. It is to boldly insist on the honest recognition that all data is filtered and interpreted; so it
matters a great deal what the composition of those filters are, and what are the a prioris that guide interpretation of the data. The great
certainty near at hand to all is the human nature we all share. Creation and catastrophe are not "irrational" starting points, except in the minds of those with a vested interest in cutting such explanations out of consideration.
If deliberate misrepresentation was used in the early-going to discredit a whole school of thought that evaluated the data coming in from a "Bible-is-reliable" standpoint, and later if the new dominant position is retrofitted with substitutions ad infinitum (as long as
revelation is rigorously excluded), then biblical a prioris haven't actually been discredited by hard scientific study; just dismissed, and replaced by fantastic "Just So" stories, in lieu of anything more rational.
The single, important thing for the evolutionaries is to keep "God" from interfering with their naturalistic program.
2) I don't know what happened to the dinosaurs. I suppose most of the bodies/bones of these were buried in the flood. The post-deluge world was a vastly different environment than the one prior; perhaps greatly inhospitable. Therefore God let them perish in the flood. He was not under any obligation to deliver any, other than to fulfill his promises. And the manner of his fulfillment is also up to him. If any such species were taken aboard the ark, they may not have survived long after the flood. I'm not sure anything more needs to be said from the standpoint of one committed to the priority of revelation.