Q: This isn’t a question, but a comment about a WNYC show. You were discussing the term “plaster of Paris” and its origin. Paris was indeed a center for the production of gypsum-based plaster. I live on the hill of Belleville, previously a village near Paris known for its vineyards and gypsum quarries. Even today, the presence of these quarries is felt.

We say that Belleville is a “gruyère,” or Swiss cheese, full of holes. One of these holes just down my street is currently being filled. The porous soil also leads to the formation of underground rivers and streams, and the area was first exploited by monasteries that created a network of underground aqueducts. Several access points, known as “regards,” remain today. Our street names show this heritage: rue des Cascades, rue des Rigoles, rue de la Mare, all related to water. Here’s a link to a “regard” up the hill.

A: Thanks for the very illuminating e-mail, and for the beautiful picture. What gorgeous old stone! How lucky you are to live there. Must be fascinating. Meanwhile, regards!

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