> Problem circumvented: After reinstalling, I used newfs from w/in netbsd to
> rebuild the filesystem on my /usr partition. It did not affect the root
> partition in any noticable way, i.e. I can still boot, etc.

Great!  But beware, the Installer will trash the /usr partition if you
try to mount it within the Installer.  Newfs creates a file system
whose format the Installer doesn't fully understand.

> I still don't know why the filesystem wasn't clean if it was just made, 

It's the same reason.  The clean flag was introduced after the
Installer was written, so the Installer doesn't know how to set or
clear the clean flag, or even the very existance of the clean flag
itself (well, at least it was the case for Intaller 1.0... how about
1.1?).

> nor do I know why the superblock was wrong on it. I am still concerned 

This one, I'm still at a loss...

> that I have overlapping partitions but I'm sick of reinstalling netbsd. 
> I'm going to be a user now, and time will tell...

Good luck!

ken