I give many lectures to students about surveying and use many USGS 1:24,000 quads to illustarte the affect of surveying on the  cultural landscape:  Metes & bounds in New England and other parts of the the Eastern U.S., township & range for many western sites, and some quads from the Great Lakes and Louisiana to illustrate the French influence (long lots/ribbon farms).

Relative to the French "pattern", the lot pattern is normally narrow and runs back from the river frontage.  However, one quad sheet has several lines that baffle me.  Could someone please explain the radiating lines on the Fitler Quadrangle, Mississippi-Louisiana?  These are in the northwest corner of the sheet.

The only thing I can think of is that the Mississippi  River changed course in this area and that maybe the radiating point was at a sharp bend in the river.

Will appreciate any light on this question.

Jim Minton