I betcha it was this:
The text described their theories regarding the single object that appeared to be most widespread and most revered. After all, steel had rusted, concrete crumbled, and this one thing had endured. (The enviro-nuts hadn't enforced plastic bags as a means of saving forests at the time the piece was written).
Must have been religious, some sort of sacrificial basin or font.
The serpentine tunnel at bottom might be a symbolic tunnel to the underworld or afterlife.
It must have been a prized family icon because it was obviously expensive to build such a long lasting object.
And so forth until they'd "scientifically" elevated a standard flush toilet to symbolize modern western civilization.
I betcha it was this: