I googled:
textbooks 30 years ago USA english
and my 4th hit was http://forum.thefreedictionary.com/postst326p4_Spelling-dilemna.aspx
Although it is about what I was looking for I was looking form a different angle, funny it came up so high.
Lemma:
1. A subsidiary proposition assumed to be...
Quote:
I never spell 'it' with an 'n' one I and one T are good enough.
But really I never spelled Dilemma with an 'n' lets see:
Dilemma
Dilemna (this one got flagged by US/English spell check on firefox)