Not many photos of Exposition Park, but the following website shows the pitching mound and home plate connected with infield dirt. The backdrop appears to have been the Allegheny River and the Point.
http://www.brooklineconnection.com/h...itionPark.html
Digging deeper on the web for more photos and came across an auction for a remarkable collection of photos from opening day 1904. Now I'm researching all the marvelous billboards.
http://loveofthegameauctions.com/190...-LOT17699.aspx