Though I know from your previous questions that you are not interested in the facts or in evidence, I will answer your question for the sake of those who might click on it.
There are a vast number of geologic strata, or layers, that were laid down over hundreds of millions of years. These layers were, in large part, initially described by geologists in the early 19th century. These geologists, incidentally, were creationists, but since at that time creationists were not enamored of trying to disprove evolution (Darwin had not yet published his book), they honestly described their findings. To this day, though much new information about the geologic column has been discovered, the descriptions of the early geologists still pretty much hold for the most part.
Because of the way the layers were laid down in different areas of the world and because of erosion of some parts of the layers or inaccessibility of other parts, there is no one location that displays the full sequence. However, the layers from different areas can be matched up and the full sequence can be pretty well laid out.
There are literally thousands of layers, and in some locations they are tens of thousands of feet thick, and they are made up of alternating and varied types of material, showing that they were laid down under widely varying conditions, such as desert, forest, river, lake, etc. They also have fossils that show an evolutionary sequence through time. In the oldest layers, only fossils of primitive, simple life forms are found. As you follow the strata from older to younger you will find a progression of life-form fossils showing an evolutionary change over time.
What is clear is that these large numbers of different strata with different types of fossils could not possibly have been laid down by the mythical biblical flood. Such a flood would not have left multiple strata. It would have left essentially a single layer.
In light of that, let's take a look at why the geologic column is evidence against the biblical flood.
According to the creationists, all species (or basic kinds--whatever), living and extinct, were created at the same time and the fossil record was laid down by the biblical flood.
If that were the case, you would find fossils of the approximately 5,000 present-day species of mammals, including humans, and of the approximately 10,000 present-day species of birds, mixed in with the fossils of, for example, dinosaurs. You do not and will never find such a mixture. That is because they are separated in time by more than 60 million years and the fossil record reflects that fact. The only fossils of mammals and birds that are found in the same strata as dinosaurs are primitive types quite unlike anything that exists today (even if you consider the "kinds" that creationists refer to as the source of present-day mammals and birds). And you will also not find those fossils of present-day mammals and birds in the same strata with trilobites, or of numerous other early types of animals.
In the Cambrian strata, which was laid down long before the time of the dinosaurs, you will find the initial appearance of most of the phyla, but they will be only very primitive species--none of which exist today--belonging to those phyla. You will not find one single amphibian, reptile, dinosaur, bird, mammal, or teleost fish.
And that scenario even continues after the demise of the dinosaurs. As you progress through the strata you will find new forms, but still nothing like what you would find today until you get to relatively young strata. There are numerous strata which show that mammals became predominate for several tens of millions of years on up to today. But the strata that was laid down during the first half of that time contains a large number of fossils of mammals quite unlike anything that exists today, and again, none of the fossils are of present-day mammals, including humans, and present-day birds. As those strata get progressively younger, you begin to see more and more fossils of mammals and birds that are similar to the present-day species. That includes hominid fossils, which are present only in the strata laid down in the past few million years. Hominid fossils are totally absent in the vast number of earlier fossil-containing strata.
Thus, if you look at the geological strata, you will find a changing representation of species through the oldest to the youngest strata, and those changes reflect an evolutionary process. That is not what you would find if the fossil record had been laid down by a flood such as that described in the Bible. But it is what would be expected in an evolutionary scenario.
This is not a matter of interpreting things according to one's belief, as creationists usually say. It is a matter of honestly accepting the evidence for what it says. The Bible believer holds that all things must be interpreted according to the Bible. Therefore, they are are forced to be dishonest in interpreting the evidence.
The geological strata indicate an evolutionary progression. If there was no evolutionary progression, but all species (or kinds, whatever) had been created at the same time, then there would be no evolutionary progression in the strata. That is fact.
In addition, certain geologic formations show quite well the impossibility of their being laid down by the mythical biblical flood. One example is the Green River Formation in the American West.
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of inter-mountain lakes. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The average thickness of a varve is about 1/8 inch. Typical Eocene fossils are found in the formation.
http://www.indiana.edu/~ensiweb/lessons/varve.ev.pdf
I would like creationists to explain how the mythical biblical flood could have laid such a formation. It would have had to deposit more than 100 varves each minute of the flood.
http://en.wikipedia.org/wiki/Geologic_column
http://en.wikipedia.org/wiki/Geological_strata