Three ways to describe land
A legal description must identify one parcel and only that parcel. Three systems do the work: metes and bounds, lot and block from a recorded plat, and the federal rectangular (government) survey. A street address is not a legal description, no matter how many times a contract uses one.
Metes and bounds
A metes and bounds description runs by bearings and distances between monuments, starting at a point of beginning, and it must close by returning to that point of beginning. That closure is the defining requirement. Acreage is a result of the calls, not a required element of them, and no plat has to be recorded for the description to be legally sufficient.
Lot and block
The lot and block method describes land by lot number, block number, subdivision name, and the plat book and page where the plat is recorded. The recorded plat is incorporated by reference, so the plat's lot and block lines supply the boundaries. Dimensions are never implied from some county standard, and registering a subdivision name fixes nothing — the recorded plat does.
Georgia is outside the rectangular survey
Georgia rule: the Public Land Survey System does not cover the original thirteen colonies, so Georgia is not in the rectangular survey and never was. Georgia land west of the Oconee was distributed by eight state land lotteries and surveyed into numbered districts and land lots; eastern Georgia used headright and bounty grants. Districts and land lots are a separate state grid, not township and range under different names, and Georgia did not "abandon" a system it was never in.
The rectangular survey numbers
You still must know the national system. Sections are numbered beginning with 1 in the northeast corner, snaking back and forth to 36 in the southeast corner. A township is 6 miles square — that is 36 square miles, not 6 — containing 36 sections of 640 acres each: 36 × 640 = 23,040 acres.