With acknowledgements to S M Clabby of DinoWight in the Isle of Wight.

Sedimentary rocks develop over time, so younger rocks are laid down on top of older rocks. This means that the closer to the surface the younger the fossils that are found in the rock. There are other dating methods as discussed here.

The fossil record is a good way of seeing how life has developed on Earth. We have only an imperfect fossil record, but we have found many fossils that give a snapshot of life millions of years ago. If we look at particular environments, we can see whole ecosystems as they were when the rocks were laid down. For instance, southern England was seasonally flooded during the late Cretaceous period. We know this because of the Wealden group of Southern England (see here Wealden group page on DinoWight for a detailed discussion) which has clays that contain fossilised plants which typically grow in that sort of location The best example of which is Weichselia (Half way down This page is a picture of this fern) which is like the Cretaceous equivalent of the mangroves. The form of sediment is also indicative of a flood plain. Modern examples of these include the Pantanal of Brazil and the Varzea flooded forest of the Amazon Basin. In these places there is a great deal of sedimentation and deposits of clays. The same form of sediments are found in the Wealden formation, leading to the conclusion that the same process was involved. The fact that we have mangrove like plants in this layer substantiates the claim. There is, amongst these plants, Iguanodon footprints, and there have been Iguanodon, Polacanthus and Brachiosaur fossils have been found. The footprints show that dinosaurs were walking around amongst the Weichselia. Crocodile fossils have also been found, such as Goniopholis. From this evidence we can build up a picture of what this area would have looked like when the dinosaurs that left the footprints lived there.

The form of sediments and the types of plants show that what is now southern England was a tropical floodplain. The footprints and fossils show what animals lived there. This is the most parsimonious explanation. If there is a rival explanation, it must deal with all the points that are mentioned here. It must explain not only why those animals and plants are there, but also why other types of animals and plants aren't there. It must deal with how the fossilised footprints are found.

Not only do bones and footprints get fossilised, but other things do. worm burrows, sand-dunes and many other details that would be destroyed in a catastrophe are found right through the different sediments. These give a detail that is almost unbelievable and gives us information about how these creatures once lived.

An excellent example of this is in the Grand Canyon. Sandwiched between two sections of limestone is a layer of sandstone. Limestone is formed by sediment formed by water. So, in the Grand Canyon, we have two different times when the area was totally submerged with a desert between them (details taken from http://www.kaibab.org/geology/gc_layer.htm).

The top limestone is called the Kaibab Limestone, followed by the Toroweap formation. They contain fossil brachiopods, corals, molluscs and crinoids (sea lilies). This shows that the last thing recorded in the geologic record is a sea

The level below that is a level of sandstone. This is known as the Coconino sandstone. This is made from sand dunes. The particular wedge shaped cross bedding shows that they are sand dunes. On these sand dunes there are invertebrate tracks, so creatures lived on these dunes.

Underneath that is the Hermit Shale. Shale is a mudstone, and it contains ferns and conifers. There are also tracks from reptiles and amphibians.

The Supai formation is the next lowest. This is back to limestone. marine limestone at the Western end changing to estuary formed limestone. This can be confirmed because of the fossils, which consist of marine fossils at the Western end and changing to terrestrial plants, amphibians and reptiles at the Eastern end.

The above formations show that in the top layers of the Grand Canyon there have been two times when it was flooded and there was time for a desert to form between those times. Any other explanation of the Grand Canyon must explain these features. A year long single flood does not explain this at all.

In all parts of the world, we have generally, the same features appearing in the same order. There are places where the order is reversed, and these are always where there is a lot of evidence to show major geologic activity. There are also places where sections are missing. These are understood to be places where they have worn away. This would fit into the theory. What would not fit in would be a place where they are jumbled up.

What needs to be appreciated about the geologic column is the order in which the fossils are found in. Flowering plants, mammals and birds all appear towards the top of the column and are never found in-situ further down.