Final answer:
Devonian rocks are often represented by a specific color or symbol with the label 'Dv' on geologic maps, and those rocks may typically include sedimentary rocks and Devonian-era fossils.
Step-by-step explanation:
The symbol used to indicate rocks that are of Devonian age is not uniformly standardized across all geological survey organizations, but in the context of a typical geologic map or exercise, Devonian rocks may be represented by a particular color or symbol accompanied by the label 'Dv'. In many cases, the colors for geologic units are derived from a geologic time scale which can vary depending on the illustration or publication. In educational exercises, it is common to use a chart or legend that clearly defines what each color or symbol represents for the Devonian period. Devonian rocks might include sedimentary rocks such as sandstone or limestone and are often associated with the presence of fossils from the same period. Those maps and exercises would use these color codes or labels to help students identify the correct rocks during geological studies.