On a world map the co-ordinates for the city of Liverpool ลิเวอร์พูล are 53o latitude north and longitude 3o west. Liverpool is a metropolitan borough of Merseyside and a unitary authority in its own right. However, it also still retains historic links with the county of Lancashire, to which it was once part of. The Merseyside metropolis derives its name from the River Mersey and encompasses the cities and towns along its banks, estuary and hinterland. Liverpool is on the eastern bank of the River Mersey and is the fifth largest in England, with a population exceeding 440,000 in an area of around 11100 hectares. The population density in Liverpool is about 40 per hectare.
It has been established that there were settlements along the banks of the River Mersey, in the area we now know as Liverpool, dating back to the 1st century AD. These settlements would have been small fishing communities which, over the centuries, amalgamated into a heavily urbanised area by as early as the 12th century. The surface geology of Liverpool is rarely more than 10 metres thick and is a pebbly silty clay, with some sand and gravel deposits, which were all laid down by the retreating glaciers during the last ice age. The dominant bedrock in Liverpool is sandstone that was laid down in the Triassic era around 250 million years ago. To the west, the city also borders on to Carboniferous shale, mudstone and sandstone deposits as well as the Lancashire Coalfield deposits. At one time the coal deposits were workable but now, with most of the remaining deposits being below 1200m they are deemed unviable economically. However, the potential of coal bed Methane as a source of potentially clean energy is being studied, which might result in the coal deposits having a further use. In the early 1990s an oil and gas field was discovered in Liverpool Bay, out beyond The Wirral. Capable of producing 10 million cubic metres of gas and 70,000 barrels of oil a day, the field is now economically important to the area with an annual turnover exceeding £60 million. With supplies of sand, gravel and clay all available locally the traditional building materials used in Liverpool have been moulded bricks and clay tiles for roofing.
Liverpool technically extends along 21km of the east bank of the River Mersey estuary, rather than being on a river that actually flows through it. The Mersey is formed at the confluence of the River Tame and the River Goyt at Stockport in Lancashire. The famed Manchester Ship Canal joins the river at Eastham Locks and was the route by which imported cotton into the port at Liverpool was transferred to Manchester and the other weaving towns of Lancashire. Although the city of Liverpool has developed around a ridge of seven distinct hills the land rarely rises above 50m, with the highest point being at Everton Hill, 70m.
The climate in Liverpool is typical of England being a temperate one. With most of its weather systems arriving on the prevailing westerly winds, the average temperature in January is 50C and July it is 150C. On average Liverpool receives less than 750ml of rainfall a year which, considering its location on the west coast of England is surprising. However, the landmass of Ireland, to the west, absorbs much of the rainfall coming off the Atlantic Ocean that would otherwise fall on Liverpool. The average expectancy of rain in Liverpool is about 175 days a year. The temperature in January is higher than might be expected for a city in the north of England. This is because the city, and its port, benefit from the blanket effect of the North Atlantic Drift.