Each Section within a Township contains four Quarter-Sections. A Quarter-Section is exactly what the name implies, 1/4th of a Section, typically 160 Acres measuring 1/2 mile by 1/2 mile.
The four quarter-sections in the map at right are the northwest, northeast, southwest, and southeast quartersection.
Developed lands and lands grants, usually use "block and lot" measurements as well as "meets and bounds". There are always exceptions, but for the most part, this is usually the case.
Please Note: NW 1/4 and NW4 both mean Northwest Quarter, and are both acceptable in legal descriptions. However, never mix the two methods in the same legal description.
Public Land Survey System ... Page 4