Interviewer: Can you explain this gap in your resume? Geologist: Erosion was taking place and there is an unconformity. We have a fairly good idea how long I was doing things, but to know what I was doing we'll have to look elsewhere. Preferably underwater.
Interviewer: Can you explain this gap in your resume? Pre-modern military historian: sources for those campaigns are both late and fragmented. We can be reasonably sure that not only did I do work, I won the campaign, but precise details on work composition, tactics and leadership remain uncertain.