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.
Su geografía física es en gran parte montañosa. Posee suaves playas en su litoral del Pacífico y planicies bajas al norte del país. Es atravesada en su parte central por la cordillera de los Cuchumatanes y parte de la sierra Madre del Sur.
