What is this defect on stoneware bottle?

[PAX_in_MA]

Wrongly posted about this bottle in the pre 1900 forum. Not knowing much if anything about stoneware, have been doing a lot of research and noticed that a lot of stoneware bottles have similar glaze patches/stains. I know it's not it and that it is original but looks like if somebody repaired the bottle with epoxy. What is it, and does that help with the dating? Found the bottle in a river near Boston, MA.

 

[Harry Pristis]

It's almost certainly a contaminant in the glaze or in the kiln while the glaze and contaminant are both liquid (vitrifying). Whatever it was, it seems to have flowed a bit before it vitrified along with the bottle and glaze.

 

[Mike227]

Stoneware collectors call them turkey droppings. It is from using salt to glaze the piece. They would toss salt into the kiln when the tempeature was at its highest point and the salt would crystalize and coat the piece of stoneware. However the salt would also coat the inside of the kiln as well and the ceiling. And after lots of firings eventually they would build up on the ceiling and start to drip off unto the pieces being fired. Eventually the workers would go inside and scrape it off the ceiling as they typically did not like it on there piece’s and would make them less desirable. However now some people like them and they do add character to pieces as well.
nice bottle