diff --git a/library/lists.yap b/library/lists.yap
index c00d4495c..3bb4198be 100644
--- a/library/lists.yap
+++ b/library/lists.yap
@@ -135,7 +135,7 @@ find_nth(N, [_|Tail], Elem) :-
 
 
 generate_nth(I, I, [Head|_], Head).
-generate_nth(I, IN, [_|List], El) :-
+generate_nth(I, IN, [E|List], El) :-
 	I1 is I+1,
 	generate_nth(I1, IN, List, El).
 
@@ -184,7 +184,7 @@ find_nth(N, [Head|Tail], Elem, [Head|Rest]) :-
 
 
 generate_nth(I, I, [Head|Tail], Head, Tail).
-generate_nth(I, IN, [_|List], El, Tail) :-
+generate_nth(I, IN, [E|List], El, [E|Tail]) :-
 	I1 is I+1,
 	generate_nth(I1, IN, List, El, Tail).