Formation

{
  "id": "MLC-T-OAG-001531",
  "term": "Formation",
  "field": "Oil and gas",
  "definition": "The fundamental unit of lithostratigraphy: a body of rock distinguished by its lithology and stratigraphic position, thick and extensive enough to be mapped at the surface or traced in the subsurface over a wide area. Oilfield usage also applies the word loosely to any rock interval a well penetrates. Formations are combined into groups and may be divided into members and beds.",
  "subject": "Geology",
  "url": "https://mlchart.com/terminology/oil-and-gas/formation/"
}