These forms changed over the two to three hundred years black glass was made.
Black glass is the glass found on many of the early ship wrecks found off our coasts.
-The glass is clear (colorless) with just the slightest "straw" tint when looking through the thick portion of the base.
Early American glass blowers were from the European continent and brought with them this technology which had been used since at least the early 1600s.
Bottle designs varied from country to country in Europe, with each one creating slightly differing forms.
The two primary distinguishing features you really have to watch for are the thickness (and weight) of the glass used in production, and the type of pontil scar within the basal cavity or "kick-up".
With some exceptions, early English black glass was thicker and/or heavier than what was normally used in the manufacture of "Dutch" bottles of very similar design.