I have a few Dutch onions from Guyana also. Occasionally they do find English bottles. I'd really love to find an early English bottle from Belize - apparently they are quite abundant, but there's restrictions on their export.
Attached a picture of the James River English Onion - note the rather unique blue color that appears in natural light (possibly glass gall - reused glass/ other impurities). This style is similar to yours from the Suwannee. The narrower, longer neck and tooled V string rim places it around 1710. But as we know, the styles overlapped a fair bit.
I sure didn't see an English onion in Guyana. Any that are found must be quickly filtered out of the commercial stream to be offered to select customers. Later, I was offered a pancake onion from Guyana through a Guyanese dealer, but we couldn't get together on price.
Van den Bossche provides a good explanation of glass gall, an interesting phenomenon. I have an extra copy of Van den Bossche's book, still in the publisher's shrink-wrap, that I might trade for decent black glass.
Here's another "Dutch" onion from Guyana:
Last edited by Harry Pristis; 04-01-2017 at 02:48 PM.
Glass gall is a contamination with sodium sulphate (Na2SO4) of a glass batch or of individual bottles from the batch. The common source of this contamination is ground blast-furnace slag. Here ground slag was used as the "sand" in a sand pontil.