Identify the two ways to match up, or correlate, exposed rock layers from two different places.

Lithologic correlation and Fossil correlation - Lithological correlation is the use characteristics of rocks that may be physical or chemical to find that spatially isolated strata were once continuous. Fossil correlation, also known as Index Fossil correlation uses fossils with known stratigraphic ranges to determine the approximate correlation of two rock bodies.

Correlation Is The Matching Of Rock Layer From One Area To Another. For Example A geologist might wish to Know if a Layer of mine stone in NY is the same layer of limestone found in mi. correlation can be useful because useful valuable minerals can be found in specific layer of rock and if we can identify the same layer far away we might be able to exploit the resource over a large area. Rock Layers can be correlated using two method 1. By similiraties in the rock 2. By examining key beds