Checking a column value if date or text

Hi!

I have a problem in my SQL.
I have a table named tblseaexport with columns, ShipmentID, Remarks. Remarks columns is set with a TEXT property. My program in vb.net allows a user to either enter a text or date to be stored in Remarks. of course I convert first, if date, the date to string then store it in database. If I have a sample data:

ShipmentID Remarks
S000123 Advised Shipper
S000124 2014-01-24
S000125 2014-01-25

How can I select all rows where Remarks' value is in date format?

Thanks and Warm Regards,
Bob