Mysterious Sound Alerts--Can't Determine for What--Please help

[Pseudo-Fed]

My 4S is every few mins giving me the "tri tone" alert. This is the same alert I have set for a couple things (facebook for one), but those apps are not indicating alerts/badges and nothing is there when I open the app. How can I check for each app what alert tone I have set or otherwise determine if there is a culprit? Thanks.

 

[Pseudo-Fed]

Disregard. Think I determined it's Gmail, recently installed. But since not appearing in my notifications despite setting it to, I couldn't easily determine. Will post separately about that issue.