Update: A new Big Mound monument was constructed as part of the new bridge.
While searching in the Whipple fire insurance maps for the northern counterpart of the French Market on the Near South Side, I realized that the history of St. Louis’s Native American inhabitants and this northern market are intertwined.? The Mound Market (seen in the map in the extreme bottom of the image), so named due to its proximity to La Grange de Terre, or Earthen Barn, the largest mound in the city of St. Louis. The market once sat where the large memorial rock for the mound now sits, on a little triangular plot of land.
By the Twentieth Century, the site was run-down with trash-strewn streets and billboards.

Nothing remains of the Big Mound, the Grange de Terre’s alternate name, as was recently determined by an archaeological survey done by the Missouri Department of Transportation.
That’s right, the new Mississippi River Bridge goes right through the site of the old mound in between Brooklyn Street and Mound Street, which can be seen below had already become the site of foundries and other industry after the Civil War.
Ironically, MoDot is making its own earthen mound, rather eerily similar in shape and size to the original mound.
But alas, it seems that the only memorial to the mound will continue to be nothing more than the large rock (its memorial plaque long ago stolen by scrappers) and a street sign for Mound Street.
The Big Mound memorial will be re-constructed at the northwest corner of North 2nd Street and Mound Street
https://lh6.googleusercontent.com/-XUlNYZXsIHM/UNynOtWbM1I/AAAAAAAAAmU/FmU48dZd58U/s1238/RiverBridge-FullPlans+1198.jpg
https://lh5.googleusercontent.com/-AV6Txry4Vng/UNynNU4DZkI/AAAAAAAAAmM/IWWL7bWr2Is/s1238/RiverBridge-FullPlans+1203.jpg
Cool, glad to hear about this.
This is un-enduringly fascinating to me. I like the fact that dEspite my general feeling that this town doesn’t know how to hang on to it’s history, it is still worth having archeological excavations done for certain purposes. What a great thread of research is could start. I never knew what that circulAr rock memorial thing was for up on north broadway…