diff --git a/src/java/com/samskivert/jdbc/depot/DepotRepository.java b/src/java/com/samskivert/jdbc/depot/DepotRepository.java
index 3159160..8c4a4ab 100644
--- a/src/java/com/samskivert/jdbc/depot/DepotRepository.java
+++ b/src/java/com/samskivert/jdbc/depot/DepotRepository.java
@@ -149,7 +149,7 @@ public abstract class DepotRepository
      * type erasure as the loadAll version that accepts a collection of keys. Alas.
      */
     protected <T extends PersistentRecord> List<Key<T>> makeKeys (
-        Class<T> type, Collection<Comparable<?>> primaryKeys)
+        Class<T> type, Collection<? extends Comparable<?>> primaryKeys)
         throws DatabaseException
     {
         // convert the raw keys into real key records