Slate from Poultney, Vermont Vermont slates formed 475 million years ago during the Taconic Orogeny, a period of mountain building. Sedimentary rocks, such as shales or siltstones were metamorphosed, and they became slate.
Slate from Poultney, Vermont Vermont slates formed 475 million years ago during the Taconic Orogeny, a period of mountain building. Sedimentary rocks, such as shales or siltstones were metamorphosed, and they became slate.
