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.

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