Some time ago whilst browsing through a copy of the 1982 Transactions of the 5th Symposium of The International Molinological Society I came across a comment by Kenneth Major in which he mentioned (page 355) that the Museum of London had an hourglass-shaped Roman mill, which was found in London, and was similar to those of Pompeii.  He went on to say that there was no doubt that it was made of stone mined at Mayen, Germany.  I made a mental note to visit the museum the next time I had the opportunity, to see if I could locate this mill.

The reconstructed exhibit of the Pompeian-style mill at the museum is shown in the pictures I took recently (left and below).  

It was made from a single piece of rock in the form of two hollow cones, the upper inverted cone forming a grain hopper.  The museum states that the catillus dates to the 1st to 2nd century and was imported from Mayen.
 

However, I noted that Martin Watts in his book The Archaeology of Mills & Milling (page 46) states that this catillus is from lava from the Volvic region of central France.

In operation a donkey, mule, or horse (and sometimes slaves) walked around the mill turning the upper stone and ground the grain between it and the conical lower stone (meta).  

These mills are rarely found in Britain but they are said to be common throughout the former Roman Empire.  Although most of Roman London’s food was produced locally, much of its grain was probably brought in from East Anglia and Kent, and some may have been imported from the continent.

Pompeian-style mill

Further reading:

Peacock D. (2013), The Stone of Life – Querns, Mills, and Flour Production in Europe up to cAD500, The Highfield Press, Southampton.  

Chapter 5:  Of men and beasts – the Pompeian-style mill, page 77-97.

Acknowledgements:

Sarah Williams, picture researcher at the Museum of London for permission to use my own images.