Can't delete an iCloud calendar

I have a gmail account as an iCloud calendar. I don't remember how it got there, but it is the email address associated with my iCloud account as well. Problem is that it duplicates all the calendar entries for a separate shared iCloud calendar. I thought I could just delete the gmail iCloud calendar, but it just persists after the usual right-click->delete sequence in iCal. Going through iCloud.com just throws an error and I can't delete it that way either. Ideas?