Many of Pierre's descendants in Missouri were lead miners and lived in Old Mines, Potosi (Mine a Breton), and Mineral Point. Many of our ancestors can be found in the church records for St. Joachim's in Old Mines.
In the mid 1800's some moved West when lead was discovered in Granby and Joplin. There was a Mesplay mine Southeast of the Granby Cemetery.
The Mesplay spelling was typically used in Missouri.