To separate it from the Unsubscribe function, Google is moving the Delete Calendar button to a different page. This began to slowly roll out to the UMICH domain this week. It will no longer be located under Settings -> Calendars. It will now be located in the Calendar Details page for each calendar. Hover over the calendar in the left-side list and click the drop-down menu to select Calendar Settings.
Navigation to access the new location for deleting a calendar:
New location for deleting a calendar: