In the 17th/18th/19th centuries "Indian corn" referred to any variety of what we now consider simply "corn" -- the kind that grown on a cob. It was specified as "Indian" corn, since in those days "corn" was used to simply mean grain or cereal, and could refer to barley, rice, wheat, etc... The distinction we note today between "sweet" corn (the kind we get in the local produce department) and "maize" (or Indian corn) did not exist until this century when the sweet corn varieties were developed. I would take any 1800's reference to Indain corn as being simply the normal corn of the day -- which today we probably would think was only good enough for hogs, but back then was a dietary staple.