--- a/scripts/plot/surfc.m
+++ b/scripts/plot/surfc.m
@@ -45,7 +45,26 @@
   drawnow ();
   zmin = get (ax, "zlim")(1);
 
-  [c, tmp2] = __contour__ (ax, zmin, varargin{:});
+  # don't pass axis handle and/or string arguments to __contour__()
+  stop_idx = nargin;
+  for i = 2 : nargin
+    if (ischar (varargin{i}))
+      stop_idx = i - 1;
+      break;
+    endif
+  endfor
+
+  start_idx = 1;
+  if (ishandle (varargin{1}))
+    start_idx = 2;
+  endif
+
+  if (stop_idx - start_idx == 1 || stop_idx - start_idx == 3)
+    #don't pass a color matrix c to __contour__
+    stop_idx -= 1;
+  endif
+
+  [c, tmp2] = __contour__ (ax, zmin, varargin{start_idx:stop_idx});
 
   tmp = [tmp; tmp2];