High Quality Content by WIKIPEDIA articles! The European Land Mammal Mega Zones (abbreviation: ELMMZ, formerly known as European Land Mammal Ages or ELMA) are zones in rock layers that have a specific assemblage of fossils (biozones) based on occurrences of fossil assemblages of European land mammals. These biozones cover most of the Neogene and Paleogene systems (i.e. rock layers which are 65.5 to 2.588 million years old). In cases when fossils of mammals are abundant, stratigraphers and paleontologists can use these biozones as a more practical regional alternative to the stages of the official ICS geologic timescale. European Land Mammal Mega Zones are often also confusingly referred to as ages, stages, or intervals.