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Devonian Lithological Database

Age Codes

The following codes were used in the assembly to estimate the reliability of the geologic ages reported for a unit. This system is being phased out of future versions of the database.

Code
Description
A-E
Range in confidence of age report: A best, E worst
G
No age was reported, but an age was inferred
1
Reported age based on biOS®tratigraphy
2
Reported age based on superposition and correlation
3
Reported age based on radiometric dates
4
Method for age determination unreported