JDeveloper, Java & XML :: XMLAGG For Clob Fields

I am having an issue as to how we can resolve the error ..

ORA-22813 operand value exceeds system limits

I think XMLAGG on clob is creating this issue.

Create table statements :

Create table x
as
Select '42' id, to_clob(null) notes from dual;

[b] replace the to_clob(null) with sheet attached.[/b]

I am just attaching just one clob record for notes column.

SELECT XMLElement("Notes",
(XMLAGG(XMLELEMENT("Text", XMLELEMENT("CHUNK", Notes))))) -- Issue here..I think.
from x

How do we use XMLAGG for clob fields?? (Notes is a clob field from table x)