Raycast NOT ignoring layers

I have a problem where my raycast does not want to ignore any layers except for the ignoreraycast layer

            // Ray cast
     Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);
     RaycastHit hit;
     LayerMask layer = LayerMask.GetMask("Plane");

     // Do ray cast
     Physics.Raycast (ray , out hit, layer); // Hits "Event" Layer instead of Plane Layer