Question

Lower case letters that come after the capital letter(s), e.g., KJk, labeling a rock unit represent the rock unit's _____.

-structure and depth
-age range
-rock type or name
-elevation

Answer 1

Apart from colors, geologic maps also use letter symbols to denote a property of a rock unit. Letter symbols are a combination of a capital letter followed by lower case letters. The capital letter represents the age of the geological unit, while the lower case letters represent the rock type or name.