Timelines of geology. There are several ways to measure and present the timlelines of Earths history. It is not an easy field since there are several ways to divide and present them and some changes are made all the time when the scientists come to new agreements on where to draw the lines.

The biggest geological term used is the Super-Eon (Eonothem eon). The only super-eon named is the Precambrian. It is used as a combined name for all the time before the Cambrian period, in wich life on earth started to grow greatly in numbers. Its not a dead period, but theres not much life.

The Eon (Erathem eon) Phanerozoic is the timeperiod in wich abundat life has existed on Earth. It covers roughly the last 545 millions years and is the collective name for all the periods of Cambrian, Jura, Silurian, Perm and so on. It is the current Eon in wich we live in.

An Eon is divided into Eras. The Paleozoic is the era that includes the oldest periods of more complex life on earth.  

And then Eras are divides in to System Periods like those already mentioned (Jura, Perm and so on). These are probably the most known divisions of time to people.

The system periods are then divided in to Epochs, like Upper, middle and lower Jura.

And then finaly in more detailed charts the system periods epochs are divided into stage ages (or "ages"). There are roughly a hundred of those. But the Precambrian super-eon is not divided in to these small divisions. In the precambrian the System Periods are the smallest divisions named. This due to the fact that those ages.

To make it even more complicated, geologists from some countries give alternate names to some periods. In USA the period of Carboniferous tends to become divided into the Missippian and Pennsylvanian periods instead. These terms are however not used outside the USA.

In an undisturbed stratigraphic layer the sedimentary bedrocks will lay in an orderly manner like this below. That means in sedimentary rocks that the older the rock gets, the further down in the strata its located.

But its much more common that the bedrocks are disturbed by movements like the picture below shows and sortering out the layers correctly takes a lot of knowledge and scientific tests. That is why analyzing a strata is a science, its nothing you can do without the proper knowledge.