A record of geologic materials with depth based on data obtained beneath a point on the land surface and representative of types, depths, and thicknesses of materials beneath that point. The data may represent visual observations, physical/chemical characterizations, and/or geophysical properties. The record also contains information on wells (drinking and monitoring), where appropriate.

Geological, formation attribute, and hydrocarbon potential data obtained with special tools and techniques used downhole.

Well Log - A detailed record obtained during well drilling, correlating with depth information such as changes in electrical resistivity, spontaneous potential, radioactivity, and rock type.

a document containing vital information on the history of the well and the ground surrounding it