Thanks for the lead. As a result I was able to find a picture of an antique jelly jar with the following info that I thought I'd share:
Vintage from the 19th century
Material
Glass
• Horseshoe with Hoof
• Grinder Catch or Jelly Jar
• Crystal, Clear
• Antique Early American Pattern Glass (EAPG)...
Found this piece of sea glass. Looks like the base of some kind of bottle. You can clearly see a horseshoe. My friend who owns horses says it's the bottom of a horse's foot. Has anyone seen a bottle with the base etched in a horseshoe design?
Thanks for any leads.