Last week, I asked: What kind of turtles are these, photographed these turtles on the Delaware River on Saturday near Upper Black Eddy, Pa., and how did they get their name? 

They are Northern Map Turtles, and the patterns on their shells resemble maps.

Note the distribution map on right (which does not remeble the maps on their shells). The turtle has a unique disjunct population on the Delaware River.

More on Northern Map Turtles here.