Here are some Rigsby land and tax records that I have found in my searches. Also see message 721 on this forum for the Bureau of Land Management records (though most of them are repeated here with more detail).
For some of these entries you will see the land described as, for example, "W 1/2 SW 21 2 SOUTH, 16 WEST" or "SWNE Tallahassee No 4S 15E 24". This notation is referred to as "aliquot parts", and is how land was sold when states after the original 13 were opened up for settlement. New territories were divided into "townships", which were then divided into "sections", and then further subdivided for sale.
Each territory was assigned a "meridian", which is a line that runs NS through it. A meridian has a "base line" that runs EW and intersects it. A township is an area 6 mi on a side, and is named by count and direction away from the intersection of the meridian and its base line. Distance EW is referred to as Range. For example, the northeast corner of Township 5 South Range 7 West would be 24 miles south and 36 miles west of the main intersection. A township is generally divided into 36 sections, 1 mi square (which is 640 acres). Sections are numbered in horizontal boustrophedon from the NE corner. The section was divided into halves or quarters, identified by direction (e.g.: S 1/2 or SW 1/4). The quarters were further sub-divided as necessary (e.g.: S 1/2 of SW 1/4 of NW 1/4). Uneven sections were divided into "lots", which could be pretty much any size.
The first example above would be "west half of southwest quarter of section 21, township 2 south range 16 west" (80 acres). The second would be "southwest quarter of northeast quarter of section 24, township 4 south range 15 east, Tallahassee Co (FL)" (40 acres).
[Boustrophedon: Going in opposite directions on alternating lines; right-to-left, then left-to-right. I've never before had a chance to use that word in a sentence.]
If you want more information about anyone in here, make a note of their R-number and go to my main Rigsby page:
On that page are links to all the Rigsby progenitors. The part to the left of the first dot in your R-number tells you which is yours. From there, follow the children whose birth order corresponds to each segment of your R-number until you get to the Rigsby in question. For example, to find R05.5.7.1, start with R05 James, then his fifth child (James II), then James II's seventh child (James W), then James W's first child (James Walter).
If you have information about anyone here who doesn't have an R-number, please contact me.
Note: These links all worked at the time I visited them, but may or may not now. In some cases the target site may have been rearranged, so you might have to re-search that site to find the Rigsby records.