Here are five answers to the call number query.
-----------------------------------------------
1----

Annette:

I don't catalog maps any longer, but my memory is that 1990z indicates that
the cataloger didn't know the exact date but guessed that the date of
situation of the map was in the 1990's.

Chris Kollen
[log in to unmask]

> --- Begin Forwarded Message ---
> Date: Wed, 2 Feb 2000 09:22:28 -0700 (MST)
> From: Annette Vigil <[log in to unmask]>
> Subject: call number query
> Sender: Annette Vigil <[log in to unmask]>
>
> Map Catalogers out there,
>
> What does a letter "z" indicate at the end of a year in a map call number?
> i.e., 1990z
>
> I looked in the LC G schedule for an explanation of it, but couldn't find
> any.  Thanks.
>
> **************************************************************
> Annette D. Vigil, Librarian             Phoenix Public Library
> e-mail: [log in to unmask]     1221 N. Central Ave.
> Phone: (602)495-5053                    Phoenix  AZ  85004
> Fax:   (602)261-8751
> **************************************************************
> --- End Forwarded Message ---

--------------------------------------------------------------------
2------

Can be added after date of PUBLICATION to call numbers to
indicate uncertain date.  Should not be used with date of
SITUATION in map call numbers.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Phil Hoehn, Map Bibliographer
Branner Earth Sciences Library
Stanford University
Stanford, CA 94305-2210
[log in to unmask]
Phone 1.650.725.1103   FAX 1.650.725.2534

---------------------------------------------------------
3------

The z at the end of a date in a Library of Congress call number is used to
indicate the exact date is unkown.  1990z means the date of situation or
publication is estimated as some time in the 1990s but which year is
not known.  The catalog record would show the date as 199-?

--
Brian Falato
Serials/Maps Cataloger
University of South Florida
Tampa Campus Library
4202 E. Fowler Avenue
Tampa, FL  33620
(813) 974-1772

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4-------

Annette,

The only situation that I am aware of in which "z" is used in a
date, and this is not unique to map cataloging, is when the date
of publication is uncertain to indicate that the last digit or
digits of the date are unknown.  In Subject Cataloging Manual:
Shelflisting, section G140 deals with dates and gives examples.
For example, if the date is given as 198-? the call no. date
should be recorded as 1980z.

Hope this helps.

Mark Crotteau
Albertsons Library
Boise State University
Boise, ID  <[log in to unmask]>

------------------------------------------------------------------
5--------

This means that the date of situation of the map is sometime in the
1990's. It is using the rule for dates in G140 section 1 in the LC Subject
Cataloging Manual: Shelflisting.


Daniel T. Seldin                             Telephone: (812)855-2059
Map Cataloger
Monographic Original Cataloging Unit         E-Mail:[log in to unmask]
Technical Services Department
E350 Main Library
Indiana University
1320 E. 10th St.
Bloomington, IN  47405-3907