Middle Stone Age
The Middle Stone Age (or MSA) was a period of African prehistory between the Early Stone Age and the Later Stone Age. It is generally considered to have begun around 280,000 years ago and ended around 50–25,000 years ago. The beginnings of particular MSA stone tools have their origins as far back as 550–500,000 years ago and as such some researchers consider this to be the beginnings of the MSA. The MSA is often mistakenly understood to be synonymous with the Middle Paleolithic of Europe, especially due to their roughly contemporaneous time span, however, the Middle Paleolithic of Europe represents an entirely different hominin population, "Homo neanderthalensis", than the MSA of Africa, which did not have Neanderthal populations. Additionally, current archaeological research in Africa has yielded much evidence to suggest that modern human behavior and cognition was beginning to develop much earlier in Africa during the MSA than it was in Europe during the Middle Paleolithic. The MSA is associated with both anatomically modern humans ("Homo sapiens") as well as archaic "Homo sapiens", sometimes referred to as "Homo helmei". Early physical evidence comes from the Gademotta Formation in Ethiopia, the Kapthurin Formation in Kenya and Kathu Pan in South Africa.
Iron Age
By convention, the Iron Age in the Ancient Near East is taken to last from c. 1200 BC (the Bronze Age collapse) to c. 550 BC (or 539 BC), taken as the beginning of historiography (Herodotus) or the end of the proto-historical period.
In Central and Western Europe, the Iron Age is taken to last from c. 800 BC to c. 1 BC, in Northern Europe from c. 500 BC to 800 AD.
In China, there is no recognizable prehistoric period characterized by ironworking, as Bronze Age China transitions almost directly into the Qin dynasty of imperial China; "Iron Age" in the context of China is sometimes used for the transitonal period of c. 500 BC to 100 BC during which ferrous metallurgy was present even if not dominant.