This photo shows ironstone formed by iron-fixing bacteria. The orange color means the iron received oxygen - browner clays come from the riverbed, where low-oxygen muck preserved more fossils.
Imagine a boggy, humid region teeming with crocodiles, freshwater sharks and dinosaurs; that's what this area looked like millions of years ago! And you can still find evidence of that era - particularly in a fossil-rich region of Maryland known as "dinosaur alley." Sabri Ben-Achour learns more from Dr. Peter Kranz, a paleontologist who runs a camp for young dinosaur hunters.
[Music: "Walk the Dinosaur" by The Goombas Feat. George Clinton from Super Mario Bros.]