Thanks, I found it. But in my case the Quotes were not in a tab but in a window at the bottom of the profile page. The particular notifications were for quotes of old messages and were buried to or three pages deep in the quotes, with no obvious way to find the actual message which was referred to.

It would be great if the Notification link, next to the number of notification took the user to a simple list of all notification of all types. I think most users would expect that.