"Street pattern" notation on charts?

Hello all!

I'm wondering about a notation I've seen on a couple of VFR sectional
charts. A small area - no bigger than about 3 or 4 miles on a side -
will be outlined with thin black dashed lines, with a note "street
pattern". The note is in the same typeface used for other landmarks
like "golf course", "plant", "hospital", etc. Does it mean something
like "unusual street pattern that is a good visual landmark"? Or
something closer to "this might sort of look like a runway, but it's
not, so don't land on it"? I've looked through the User's Guide at
http://www.naco.faa.gov/index.asp?xm...ine/aero_guide but the
answer didn't jump out at me; is there a better place to look for things
like this?

One example is about 10 miles due east of MKO (Muskogee, Oklahoma). See
http://skyvector.com/perl/code?id=KMKO&scale=2 and look east of MKO and
just north of the small town of Braggs. (For those of you keeping score
at home, this is on the Dallas-Ft. Worth sectional.) Here is a Google
Maps satellite photo of the same area:
http://maps.google.com/maps?f=q&z=14...-95.189667&t=h

Thanks!

Matt Roberds