This was recently uncovered in the work currently being done to restore Jackson Park. It was obscured by trees and brush which were cleared a couple of weeks ago. There's a base for another one of these posts nearby.

<a href="https://www.flickr.com/photos/29821940@N00/16961509820" title="1893 Columbian Expositon Light Post by WayOutWardell, on Flickr"><img src="https://farm9.staticflickr.com/8825/16961509820_5a8057fb85.jpg" width="282" height="500" alt="1893 Columbian Expositon Light Post"></a>