1. Geographic Locations:

* Cambrian: Named after Cambria, the Latin name for Wales, where rocks of this period were first studied.

* Ordovician: Named after the Ordovices, an ancient Celtic tribe that lived in Wales.

* Silurian: Named after the Silures, another ancient Celtic tribe that lived in Wales.

* Devonian: Named after Devon, a county in southwest England.

* Permian: Named after Perm, a region in Russia.

* Jurassic: Named after the Jura Mountains in Switzerland and France.

* Cretaceous: Named from the Latin word "creta," meaning chalk, which is abundant in rocks from this period.

2. Notable Features:

* Triassic: Named from the three distinct rock layers (Trias) found in Germany.

* Carboniferous: Named for its rich coal deposits, formed from plant matter during this period.

* Eocene: Derived from Greek words meaning "dawn" and "new," referring to the early appearance of modern mammals.

* Oligocene: From Greek words meaning "few" and "new," referring to the relatively small number of mammals compared to later epochs.

* Miocene: From Greek words meaning "less" and "new," referring to the further development of mammals.

* Pliocene: From Greek words meaning "more" and "new," referring to the increasing number of modern mammals.

* Pleistocene: From Greek words meaning "most" and "new," referring to the dominance of modern mammals.

3. Time/Order:

* Paleozoic: From Greek words meaning "ancient" and "life," referring to the earliest life forms.

* Mesozoic: From Greek words meaning "middle" and "life," referring to the age of dinosaurs.

* Cenozoic: From Greek words meaning "recent" and "life," referring to the age of mammals.

4. Other Sources:

* Holocene: From Greek words meaning "entirely" and "new," referring to the most recent epoch, marked by the current interglacial period.

It is important to note that the naming of geologic periods is often a combination of these factors, and there may be other interpretations for some names.