Not that dinosaurs were any more abundant there than elsewhere.

They probably ranged all over North America, and different kinds inhabited other continents as well.

But in the East and the Middle West, the conditions were not favorable for preserving their remains, except in a few localities.

Formations of this age are less extensive, especially those of the delta and coast-swamps which the dinosaurs frequented.

And where they do occur, they are largely covered by vegetation and cannot be explored to advantage.