Our planet Earth is almost 4 billion years old. Its crust has evolved through four stages, the latest being the Quaternary. The Quaternary period is further divided into Pleistocene and Holocene epochs. Man is thought to have appeared on the Earth during the early Pleistocene.
In India first human occupations appeared in middle Pleistocene around 5, 00,000 BC. The earliest cultural phase of the humans is known as Paleolithic Age (Old Stone Age).
The Paleolithic Age in India is broadly divided into three phases based on the nature of stone tools used by the people of that era-
1. Lower Paleolithic (5,00,000 BC – 50,000 BC)
2. Middle Paleolithic(50,000BC- 40,000 BC)
3. Upper Paleolithic( 40,000 BC- 10,000 BC)
Lower Paleolithic or Early Stone Age is characterized by use of hand-axes, cleavers and choppers which were used mainly for chopping, digging and skinning. Lower Paleolithic tools have been found at various sites such as Soan Valley, Punjab( Now in Pakistan); Belan Valley, Uttar Pradesh; Didwana, Rajasthan; Bhimbetka, Madhya Pradesh and other places.
The principal tools of Middle Paleolithic Age are blades, points, borers and scrapers. These are based on flakes. The Middle Paleolithic Age tools have been excavated from various sites in India and show regional variations. Important Middle Paleolithic sites can be found in Narmada valley, Son valley, Luni in Rajasthan, Nevasa in Maharashtra and other places.
The Upper Paleolithic phase was less humid and comparatively warmer. It is marked by the appearance of men of modern type (Homo sapiens). In India, this phase is characterized by the use of blades and burins. This phase is also characterized by increasing use of bone tools. These tools have been found in Andhra Pradesh, Karnataka, Maharashtra, Madhya Pradesh, Uttar Pradesh and Bihar. Humans started to use caves and rock shelters during this phase. Such caves have been discovered at Bhimbetka in Madhya Pradesh.
Paleolithic sites are found near hilly slopes and river valleys and are absent in the alluvial plains of the Indus and the Ganga. This is probably because of the availability of stones for tool making and water.

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