Perhaps a material where size and shape and wear is so important. Of 
course the original soil matrix as well. Windows generally crack into 
relativly large pieces. I never dealt with large pieces however the 
smaller ones were never worn down most likely because with any preasure 
they simply went deeper into the matrix of the soil.

Patrick Martin wrote:

> In the published version of my thesis (1985   The Mill Creek Site and  
> Pattern Recognition in Historical Archaeology.  Mackinac Island State  
> Park Commission, Archaeological Completion Report Series, Number 10,  
> 265 pp.,  Mackinac Island, Michigan.) I analyzed about 15,000 flat  
> glass fragments from three nineteenth century building ruins based on  
> thickness distributions and Moir's formulaic dating approach.   I got  
> different results than Moir did, but some interesting patterns.  You  
> might consider having a look for comparative purposes, at least.
> PEM
>
> -----Original Message-----
>
>>> From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of
>>> Benjamin Carter
>>> Sent: Friday, February 19, 2010 9:09 AM
>>> To: [log in to unmask]
>>> Subject: Plate Glass references
>>>
>>> All,
>>>
>>> I am having a bit of trouble finding references for the dating of  
>>> plate
>>> glass.
>>>
>>> There are, of course, far too many resources for bottle and table  
>>> glass,
>>>
>>> but I haven't had much luck finding out any details about plate  glass.
>>>
>>> I have mostly plate glass with a bluish cast, which I assume is soda
>>> glass. But, I also have, from the same contexts, some extremely  
>>> clear plate
>>> glass. Why are these different? I assume that 'decolorizing' agents  
>>> were use
>>> for the clear glass. Is there a time when this began. The site is  
>>> fairly
>>> well dated- 1790s-1811. Would a change in glass types
>>>
>>> have happened at this time? Or, is it likely that the clear glass is
>>> intrusive. Many of my contexts are fairly close to the surface.
>>>
>>> Cheers,
>>> Ben Carter
>>>
>>>
>>>
>>
>
> Patrick E. Martin
> Professor of Archaeology and Chair
> Department of Social Sciences
> Michigan Technological University
> Houghton, MI  49931
> phone 906-487-2070,email [log in to unmask]
> www.industrialarchaeology.net
>