While technically known now as the K/Pg Boundary, the name K/T is much more well-known!
The fantastic thing about these wonderful little vials is that they contain three distinct layers of dirt. The lightest colour at the bottom comes from the Cretaceous sediments of North Dakota, famous for plentiful dinosaur fossils and being the last time dinosaurs roamed the Earth! The upper medium coloured layer comes from the Paleogene and no dinosaur fossils are found in this layer!
The dark nearly black layer in the middle is the actual K/Pg (K/T) boundary, containing micro meteorites and an extremely high amount of Iridium is the actual layer that supports the asteroid extinction theory!
To sum it all up, below the darkest layer, dinosaurs are found, above the darkest layer, dinosaurs are no longer found!