Aha! Not quite, but that did have a link to what I did mean! The 
Appendix H "Local/Obsolete Data Elements" page at: 
http://www.loc.gov/marc/bibliographic/bdapndxh.html

Thanks!

I missed this becuase on the table of contents for the MARC 
documentation, Appendix H is just called "Local Data Elements", without 
the word "Obsolete", which left me not realizing on reading the ToC that 
that's what I wanted. Phew. Thanks!

Jonathan



Walker, David wrote:
> Do you mean just the 'CONTENT DESIGNATOR HISTORY' at the bottom of each page?
>
>   http://www.loc.gov/marc/bibliographic/bd4xx.html
>
> --Dave
>
> ==================
> David Walker
> Library Web Services Manager
> California State University
> http://xerxes.calstate.edu
> ________________________________________
> From: Code for Libraries [[log in to unmask]] On Behalf Of Jonathan Rochkind [[log in to unmask]]
> Sent: Wednesday, January 27, 2010 11:59 AM
> To: [log in to unmask]
> Subject: [CODE4LIB] marc documentation?
>
> I know I've seen documetnation on the LC site before for since-abandoned
> marc bib tags, like 400. But I can't for the life of me find it now
> navigating around the website or googling. does anyone know where this is?
>
> Jonathan
>
>