It looks like the Dawson Bros., Chicago, made a lot of artistic inserts around the turn on the 19th-20th century. They were excellent craftsmen.
This site has several examples of their work. Your's stands right up there with the very best.
(broken link removed to http://www.urbanremainschicago.com/default.aspx?pageID=40)
Here's an ad placed in the Chicago Architectural Handbook of 1908.
This site has several examples of their work. Your's stands right up there with the very best.
(broken link removed to http://www.urbanremainschicago.com/default.aspx?pageID=40)
Here's an ad placed in the Chicago Architectural Handbook of 1908.