Alcatraz Penitentiary - SOLD 3.084" Showcase Concrete plesiosaurteeth 071" fossil Ginkgo cranei leaf

071" fossil Ginkgo cranei leaf from the Sentinel Butte Formation in North Dakota

Above: The 7" size stacked with lava rocks

• Side-seamed construction

Edges can be sharp and the material may flake

Alcatraz Penitentiary - SOLD 3.084" Showcase Concrete plesiosaurteeth 071" fossil Ginkgo cranei leafThis is an authentic piece of concrete from Alcatraz Penitentiary. Yes, an actual piece of The Rock!" This particular specimen measures 3. 084" along the widest point. This specimen, from the famous Alcatraz Island, saw some 1,500 prisoners pass by it during the prison's operation. A certificate of authenticity is included.