1
general::
Rise to the surface, become visible or evident, as in These superstitions crop out time and again. This term originated in mining, where a stratum or vein of ore is said to crop out when it comes to the surface. [Mid-1800s]
American Heritage Idioms
2
general::
Phrase(s): crop out
to appear on the surface; [for something] to reveal itself in the open; to begin to show above the surface. • A layer of rock cropped out at the edges of the desert.
McGrawhill's American Idioms And Phrasal Verbs