Thank you all for the kind words and taking the time to check out my find. I am still absolutely beside myself. I didnt manage.to find anything else in that spot but about a dozen square nails. The other coins are modern lincolns and a few clad dimes that I dug in other parts of the park.
This was the only patch of vinca that had been cut back and it was right at the entrance. The vinca is everywhere so I will definitely be back in the coming weeks to check if more has been cut down. I also noticed a backhoe and skidloader doing some work around the admin building but there was no one around when I was leaving to ask if I could go over the freshly moved dirt.