About 1880, a professor of Natural Science at the University of Iowa and geologist, Samuel Calvin came to Polk County to photograph the rock formations. His gallery includes photos taken east of Mena which are mostly of geological formations in the woods. Fortunately for us who are interested in Big Fork, he took this photo of the early hotel and post office that served the community at that time. As of yet, I haven't been able to identify the three people on the porch.
Samuel Calvin was born in 1840 in Scotland and died while teaching at the University of Iowa in 1911. You can read his biography and see his photos at: http://www.uiowa.edu/~calvin/calvin.htm
Go to "Calvin's Scrapbook" and look under "Buildings". Scroll down and Voila!
If you want to see the geological images he took east of Mena, go to "Calvin's Image Database". Under "Geology of U.S. and Canada-Place of Interest" select "Arkansas" from the drop down menu and click "Go". There you will see seven photos of rock formations and a waterfall characteristic of Polk County.