I have several additional references, including coffin/casket hardware,
that may be useful for anyone working on historical cemeteries.  An
ongoing project includes excavation of a mid-size, nineteenth century
cemetery (about 44+/- graves).  We have 2 Fisk metallic caskets c. 1850s,
plus glass viewing windows on wooden coffins.  Recently acquired
references include the following:
 
Crane, Breed, and Co.
1858    "Fisk's and Crane's Patent Metallic Burial Cases and Caskets,
        Airtight and Indestructible, for Protecting and Preserving the
        Dead, for Vaults, Transportation, Ordinary Interment, or Future
        Removal.  Published by Crane, Breed, and Co. Manufacturers,
        Cincinnati, Ohio.  On file at the  Cincinnat Historical Society.
 
Another reference that includes catalogs is the "Trade Catalogs at
Winterthur". Published as a large set of microfiche with a bound index,
by Winterthur Museum.  In Ohio, it is available at the Cleveland Public
Library.  The index is available at a number of other museums.  These
catalogs include many subjects besides funeral/burial items.
 
If anyone has specific information for matching dates to different types
of glass viewing windows I would be interested.  Have found patent
dates for several types, but actual burials would be helpful.  All the
stones had been removed and deliberately "buried" at our cemetery, making
identification of any post dates from hardware very useful.  Thanks, JK