Along the western edge of Charnwood Forest the rocks are mainly Precambrian igneous diorites. These formed from molten lava deep within the sedimentary rocks, cooling slowly to produce hard, blocky rock with large crystals. This is extensively quarried for roadstone around Groby, Markfield and Whitwick, and is known as granite (formerly also called Markfieldite). The central area of the forest has older rocks still. These are sedimentary and are very variable in character, They were formed by material from volcanoes, settling in deep water, and it is in these beds that the fossils are found. Uplifting, tilting and erosion have produced the distinctive jagged exposures found across the highest parts of Charnwood. On the eastern side, a much more recent series of rocks are found. Again igneous diorites, that formed deep underground, but these are Ordovician, from a mere 450 million years ago. These are extensively quarried in the areas near Mountsorrel. The earliest form of the name Charnwood is probably derived from "cerne woda", from the Celtic "carn", meaning cairn, and the Old English "wudu", meaning wood. Some sources give "cwern" as the derivation, meaning a tool used to grind grain and other materials by hand. The area was a source of stone for these tools, called quern-stones. Archeological evidence has shown that the area was inhabited as far back as the Neolithic period, approximately 4,000–2,000 BC. Beacon Hill is the site of a Bronze Age hill fort, dating from between 600 BC and 43 AD. This forms one of the last surviving visible features in the landscape known to the Coritani, the tribe who occupied most of the East Midlands area at the time of the Roman Conquest. According to Domesday Book, there was only one settlement in Charnwood Forest in 1086, at Charley whose name would appear to come from the same root, with the suffix "-ley" denoting open land, rather than forest. In the 200 years after the Norman conquest, newly created settlements took major areas of land out of the forest for use in agriculture. Quorn was established between 1086 and 1153, and all the land up to Woodhouse had been deforested by 1228. There were comparatively few major changes in land use in the post Medieval period, until the demand for timber and charcoal for the early Industrial Revolution contributed to a further loss of woodland.