There are few roles in Org. I need find out who have created this role and when ? I could not see Created Date and Created BY field in User Role Object. Please suggest ..thanks .
There are no such fields on the UserRole object at the moment. But there is an Idea for that: https://success.salesforce.com/ideaView?id=08730000000ICep You can vote for it.
Here is some info about system fields: http://www.salesforce.com/us/developer/docs/api/Content/system_fields.htm