I have a few pages copied from a neighbor's book. It is the 1870 Muhlenberg Co. KY. Census..South Carrollton Precint No. 1. In it are members of my family line. On the side of the page is the number location of 402-A. On this page, and on many others, I see "F1." between the age and the state born in. These are not black people...which is designated by a "B". And they are not mulatto or mixed race, which is designated by a "Mu". So, what is "F1."? Thanks for your help! Thelma