Well, going by this map. it looks like some but not all parts of the Louisiana Purchase were surveyed using a starting point in RAB's fields.

http://upload.wikimedia.org/wikipedia/commons/8/83/Meridians-baselines.png

Kansas and Nebraska use their shared border as the Baseline. Montana has its own. A line running east and west that goes through the middle of Billings is where the townships start being numbered. The principal meridian is where the ranges start at. Looks to be just a bit east of Ernie's. I'm located at 27N 48E M.P.M. Not much reference to the Arkansas start point.