Bedrock is the solid rock at or below the land surface. Over much of Ireland, the bedrock is covered by materials such as soil and gravel. The Bedrock map shows what the land surface of the North East, Midlands, Cork and Dublin would be made up of if these materials were removed. As the bedrock is commonly covered, bedrock maps are an interpretation of the available data. Geologists map and record information on the composition and structure of rock outcrops (rock which can be seen on the land surface) and boreholes (a deep narrow round hole drilled in the ground). Areas are drawn on a map to show the distribution of rocks. To produce this dataset, the bedrock geology 1:100,000 map was clipped to these areas. Historical information was compiled from mineral exploration reports and old geology maps. This new information was used to re-interpret the geology. This Bedrock map is best displayed to the scale 1:50,000 (1cm on the map relates to a distance of 500m). It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas). The bedrock data is shown as polygons. Each polygon holds information on the rock unit name, its description, stratigraphy code (rock layers with age profile), lithology code (rock type) and map sheet number. Each polygon is linked to the bedrock lexicon table which has more detailed information such as a definition of the rock unit, rock types, age, thickness and other comments.