The world map reference for Plymouth is latitude 50o22’49″ north and longtitude 4o08’43″ west. Plymouth has a deep water harbour and sits on the east bank of a large estuary opening onto the English Channel. To the east and running through Plymouth is the River Plym, to the north of it are the rivers Tavy and Tamar, with the rivers Lidhey and Tiddy to the west across the estuary. Plymouth is by far the largest urban area in the South West and is the third largest city in the whole of Southern England. Covering an area of 8000 hectares it has a population of 250,000, giving a population density of about 31 people per hectare. So, as one of the major cities in England it is not densely populated. Plymouth is in the county of Devon and has been a city since 1928. In 1998 it became a unitary authority under a national re-organisation of local government. Despite being the largest city in the area Plymouth is not the county town for Devon, the honour of which falls to Exeter.
The surface rock found in Plymouth is Sandstone (to the east) and Mudstone (to the west) which lies above the Devonian bedrock, dating back some 417 million years. Hence there are a lot of limestone, sandstones, mudstones and shales. The most significant of these rocks probably being the Devonian Old Red Sandstone. Volcanic activity in the Devonian period has also given rise to igneous and metamorphic outcrops in the Plymouth area. Off the coast of Plymouth the bedrock is Limestone from the very early Cainozoic. Many older buildings in Plymouth were constructed from the local sandstone, in the area around Plymouth the local igneous and metamorphosed rocks were often used for building material. The traditional roofing material in Plymouth was slate from the quarries in Cornwall to the west of Launceston. Also nearby are deposits of sand and gravel which are extracted commercially and contribute to the economic development of the city. In the past Tin, Lead and Copper mining/extraction were important to the local economy. However, workings for these minerals are no longer economically viable. Plymouth could in the future benefit from the potential of geothermal energy arising from its proximity to the igneous and metamorphic rocks of Cornwall. Being on the south coast of England, the surface geology of Plymouth was not affected by glacial movements in the last ice ages.
Plymouth is not a hilly city; the elevation around the city centre rarely rises above 10m. However, the north of the city does start to become hilly and the elevation at the airport is about 10om above sea level. To the south of the city Plymouth Hoe, where Sir Francis Drake played his historic game of bowls, is only 5m above sea level. Travel east some 10 miles (15km) out of Plymouth on the A38 and you’ll arrive at Ivybridge on the southern edge of Dartmoor. Dartmoor is one of the original 10 National Parks created in 1951 and is famed for its pre-historic associations, numerous Tors and it’s highly changeable weather.
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