It may be hard to imagine, but over hundreds of milllions of years Warwickshire has been created by deep seas, river deltas, volcanoes, swamps, shallow tropical seas and glaciers - a far cry from today's rolling agricultural landscape.
The geology of Warwickshire is one of the most varied to be found in any English county. It ranges through many geological periods and the rocky foundations are still well exposed in a number of quarries and cuttings.
The oldest rocks of the Precambrian, Cambrian and Ordovician periods are confined to the north of Warwickshire where huge quarries have exploited them for aggregate. Silurian rocks are essentially absent, and Devonian rocks are confined to a narrow strip to the north-west of Nuneaton.The economically important rocks of the Carboniferous Period, which contain the coal of the Warwickshire Coalfield, are found north of Coventry.
The Permian and Triassic periods are represented by sandstones, which were used to build Kenilworth and Warwick castles, and red clays. These rocks underlie a large U-shaped area through the centre of the county forming the valleys of the rivers Arrow and Avon.
The Jurassic rocks are mainly clays, sands, limestones and ironstones and form all the higher land in the south and east of the country. These rocks have been used for building stone and cement making. Many are rich in fossils.
The Quaternary, commonly called the Ice Age, is represented by extensive deposits of clay, sand and gravel. Once again, these are important economically and a number of gravel pits have been opened. |