diff --git a/docs/config.rst b/docs/config.rst
index e33e035..54ddfa1 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -709,8 +709,10 @@ values. The valid configuration keys are listed below.
 .. _crop:
 
 ``crop``
-    You can use this to render one or more small subsets of your map, instead
-    of the entire thing. The format is [(min x, min z, max x, max z)].
+    You can use this to render one or more small subsets of your map. The format
+    of an individual crop zone is (min x, min z, max x, max z); if you wish to
+    specify multiple crop zones, you may do so by specifying a list of crop zones,
+    i.e. [(min x1, min z1, max x1, max z1), (min x2, min z2, max x2, max z2)]
 
     The coordinates are block coordinates. The same you get with the debug menu
     in-game and the coordinates shown when you view a map.
diff --git a/overviewer_core/settingsValidators.py b/overviewer_core/settingsValidators.py
index 0499815..2b3d28f 100644
--- a/overviewer_core/settingsValidators.py
+++ b/overviewer_core/settingsValidators.py
@@ -230,7 +230,7 @@ def validateCrop(value):
         
     cropZones = []
     for zone in value:
-        if len(zone) != 4:
+        if not isinstance(zone, tuple) or len(zone) != 4:
             raise ValidationException("The value for the 'crop' setting must be an array of tuples of length 4")
         a, b, c, d = tuple(int(x) for x in zone)