Bernard, Pam misuses the term for her item here.
Pam, I suggest you edit out "overshot" in your title
(do this by going to your original post, make sure you are logged in, click on edit and edit the title which can be found on the upper right hand side)
Bernard, There is an explanation of Overshot Glass in this article by Stan & Arlene Weitman at Angela's Glass Museum On Line
http://www.glass.co.nz/overshot.htmthe article says
"Overshot glass was made by rolling a partially or fully inflated gob of hot glass on finely ground shards of glass that had been placed on a steel plate called a marver. The gob was then lightly reheated to remove the sharp edges of the ground glass."
But re-heating to remove sharp edges was not always done. I have a piece of Murano with very sharp overshot.
There was also much discussion of overshot in this recent thread
http://www.glassmessages.com/index.php/topic,1995.0.html