Check the HISTARCH archives.  Several times over the last decade this topic has been discussed quite extensively:

lists.asu.edu/archives/histarch.html

We have excavated several large landfills in Salt Lake City and Ogden, Utah.  The former excavations cover a period from about 1890 to 1930s.  The Ogden excavations covered about 1940s-1960s.  We are currently monitoring a river restoration project where trash dumping was common from about 1880s-1900.  We have excavated several areas of dense trash from the edges of Ogden City here.  

I am on the road at the moment, but would be glad to send you references when I return.

Mike


Michael R. Polk, M.A., RPA 
Principal Archaeologist 
Sagebrush Consultants, L.L.C. 
Ogden, Utah



-----Original Message-----
From: Simmons, Stephanie <[log in to unmask]>
To: [log in to unmask]
Sent: Mon, Apr 26, 2010 12:45 pm
Subject: Dump/Landfill Studies


Hi,
I work for a CRM firm out of Portland, Oregon and we are preparing to do
 study of a community landfill in Seattle, Washington which dates to
he early 20th century. I was wondering if anyone had any good
eferences  or perhaps even reports on other dumps or landfills they
ould be willing to share?=20
Thanks much,
Stephanie Simmons
[log in to unmask]
ICF International=20