diff --git a/README.md b/README.md
index 556cdc4..a63b329 100644
--- a/README.md
+++ b/README.md
@@ -139,7 +139,7 @@ Scope and limits:
   four-cell ghost band. It gives results identical to dense storage and is
   infrastructure for future block AMR, not a speedup.
 - Several regions: pass a sequence of `(x0, y0, x1, y1)` rectangles as
-  `bounds`, with both levels blocked (`level_blocks`). Transfers are built once
+  `refinements[0]`, with both levels blocked (`level_blocks`). Transfers are built once
   from their union; adjacent, overlapping and concave unions are accepted when
   their actual dependencies close. There is no fixed rectangle-gap rule.
   The fine level is then one level-wide grid `(2*ny, 2*nx)`: