Cryptic (geology)
The Cryptic era is an informal term for the earliest geologic evolution of the Earth and Moon. It is the oldest (informal) era of the Hadean eon, and it is commonly accepted to have begun close to 4533 million (about 4.533 billion) years ago when the Earth and Moon formed. No samples exist to date the transition between the Cryptic era and the following Basin Groups era for the Moon (see also Pre-Nectarian), though sometimes it is stated that this era ended 4150 million years ago for one or both of these bodies. Neither this time period, nor any other Hadean subdivision, has been officially recognized by the International Commission on Stratigraphy.
Helladic chronology
The Early Helladic period (or EH) of Bronze Age Greece is generally characterized by the Neolithic agricultural population importing bronze and copper, as well as using rudimentary bronze-working techniques first developed in Anatolia with which they had cultural contacts. The EH period corresponds in time to the Old Kingdom in Egypt. Important EH sites are clustered on the Aegean shores of the mainland in Boeotia and Argolid (Manika, Lerna, Pefkakia, Thebes, Tiryns) or coastal islands such as Aegina (Kolonna) and Euboea (Lefkandi) and are marked by pottery showing influences from western Anatolia and the introduction of the fast-spinning version of the potter's wheel. The large "longhouse" called a "megaron" was introduced in EHII. The infiltration of Anatolian cultural models (i.e. "Lefkandi I") was not accompanied by widespread site destruction.