How could you look for unconformities on a map?

Answer 1

Look for missing time.

In other words, look for 2 rock units touching one another that are not sequential in time (look at the legend for ages). For example, a Mississippian rock layer touching a Permian rock layer. The Pennsylvanian would be missing, thus an unconformity.

Most geological maps denote unconformities in the legend with a squiggly line.