Insert a clob to XMLType

I have a table (Table1) with column type as XMLTYPE. I am trying to insert into this table (Table1) by selecting a column (of type clob) from Table2. But getting the below error -

Error report:
SQL Error: ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00210: expected '<' instead of 'B'
Error at line 1
ORA-06512: at "SYS.XMLTYPE", line 272
ORA-06512: at line 1
31011. 00000 -  "XML parsing failed"
*Cause:    XML parser returned an error while trying to parse the document.
*Action:   Check if the document to be parsed is valid.

Please advise how can i insert a clob into xmltype.