I can only guess but that could have been built that way to simply stylistically fit in with other building in the area, even if it wasn't necessary. Also, buil

I can only guess but that could have been built that way to simply stylistically fit in with other building in the area, even if it wasn't necessary. Also, building it the way they did gives more light and access to the lower level and probably required less work. Likewise I believe that many of the buildings in that area date to around the beginning of the 20th century, if not older which would put them in the right ballpark. It is also not that far from downtown and very well within incorporated Chicago in 1900 (I'll have to look for earlier maps later).