generally alters had 1 flow to collect the blood, or many to disperse it to ground. Similar grinding wheels were generally a wheel driven by donkey around in a circle, without more context it is difficult to make a conjecture. could be part of a water siphon/draw system, or base of an oven or furnace. It looks incomplete whatever it is. If it is roman, their technology was far mor sophosticated than we like to think, they had vending machines, water fountains and automatic door openers. manual grinding was abandoned long before.