Equivalence of CROSS JOIN and comma

Hi:

The PostgreSQL manual [1] reads in part:

"FROM T1 CROSS JOIN T2 is equivalent to FROM T1, T2."

Yet here are two statements that are identical to each other except
that one has a CROSS JOIN where the other has a comma:

  WITH t1 (val)  AS ( VALUES (1) ),
       t2 (name) AS ( VALUES ('foo') ),
       t3 (num)  AS ( VALUES (1) )
  SELECT * FROM t1 CROSS JOIN t2 JOIN t3 ON num=val;

  WITH t1 (val)  AS ( VALUES (1) ),
       t2 (name) AS ( VALUES ('foo') ),
       t3 (num)  AS ( VALUES (1) )
  SELECT * FROM t1, t2 JOIN t3 ON num=val;

and one works but the other doesn't.  To my way of thinking, they are not
equivalent, which makes me wonder if I am misunderstanding the quoted
text above to mean that both statements should have the same result.

What am I missing?

I am using version 9.2.0.

Thanks very munch in advance.

[1] http://www.postgresql.org/docs/9.2/interactive/queries-table-expressions.html#QUERIES-JOIN

--
Adam Mackler