Mineralogy: Similarity of the mineral composition of rocks in associated outcrops allows for their correlation, especially if distinctive or uncommon minerals are present.
4.
Position in sequence: If the lithology of a rock is not sufficiently distinctive to permit its lithostratigraphic correlation from one locality to another, its position in relation to distinctive rock units above and below may aid in correlation. In the sample shown here, the limestone unit at locality A can be correlated with the lowest of the four limestone units at locality B because of its position between the gray shale and the sandstone units. Position in sequence is aided by the presence of a unique, or marker bed, in each section.