Exactly - scroll down to the bottom on this page and you'll see concretions that look almost like the one in this article: https://www.dmr.nd.gov/ndgs/ndnotes/c

Exactly - scroll down to the bottom on this page and you'll see concretions that look almost like the one in this article: https://www.dmr.nd.gov/ndgs/ndnotes/concretions/concretions.asp https://www.dmr.nd.gov/ndgs/ndnotes/concretions/concretions.... Image here: https://www.dmr.nd.gov/ndgs/ndnotes/concretions/images/cannonball.jpg https://www.dmr.nd.gov/ndgs/ndnotes/concretions/images/canno...