Fossilization is a process that requires certain conditions so that it can take place. The climate is very important, a hot and wet place is not a place where there's a chance of finding fossils, while the places with permafrost are a much better candidate because the bacteria can not dissolve the organisms. The pressure also can play a vital role. A place that manages to keep the organisms safe from outside influence, like the tar pits, are excellent preservers. Also the structure of the organisms play a key role, a boneless organism is very hard to preserve and be fossilized, while an organism with bone structure has a bigger chance of being preserved.
The sediments that is composed of mineral grains that are
eroded from the continental rocks is called terrigenous. The terrigenous
sediments are obtained from the erosion of rocks that occurs on land and that
they are being stored in the submarine canyons.