Sorry, Joseph, I do not agree that “Only an Amorah can argue on a Gemorah, and only a Rishon can argue on Rashi.” This is not a question of Halacha, and about matters like this, Chazal are not infallible. We have seen writings of Rav Avraham ben haRambam and Rav Saadia Gaon arguing against this topic–would you say that they are not Shomrei Torah?
I have read Rav Avigdor Miller’s books, and I find him less than informed on scientific matters. He cites many sources out of context, and I must beleive that he was misinformed or mistaken. In Contrast, Have you ever read Rav Aryeh Kaplan’s books?
Concerning your information about C-14 dating–yes, it does depend on a constant rate of decay. However, we have no evidence whatsoever that the rate of decay changes. All of our assumptions are based on evidence–whereas yours have none to back them up. And there is nothing in Torah that says that we should disregard the evidence of our eyes.
About the fossil; record. You claim that there should be many “in-between creatures” and ones whose lines died out. There are indeed many of the latter forms found. As far as the “in-between” creatures–i.e. transitional lifeforms, there are reasons that we do not find them.
Consider:
The conditions for fossilization are complex. The remains of an animal or plant must find themselves on the bottom of a body of water, and get covered so they are not consumed by scavengers or decay. (The vast majority of fossils are marine organisms. We have relatively few records of land animals and even fewer of delicate land animals such as birds.) The hard parts of bodies are fossilized relatively easily, while the soft parts are not. So that creates a bias in the record. We have lots of bones and teeth, but little record of jellyfish, worms, and other fragile creatures. We estimate that the vast majority of life was soft-bodied, so the fossil record must be sparse.
Once fossilized, the remains must survive the moving of the earth (shifting, folding, breaking, etc)which will eliminate many fossils. Then, of course, the fossil must be discovered, and we have not exactly been looking for very long. Under these circumstances, it is amazing that we have found the fossils that have, and it is not surprising to think that it is not complete.
As far as the continuity of the fossil record–do you think that it is coincidence that fossils found at similar levels are thought to have existed at the same time? The science of paleontolgy is built on very careful examination of evidence, and each bit is incorporated into the theory of life. When contradicting evidence is found, we let the preponderance determine, or wait for that crucial third bit to settle the matter.