When was kansas underwater??

Question

When was kansas underwater??

Answer 1

This is what I found:

"The Cretaceous Period is a geologic time designation from 144 to 66 million years ago, when much of central and western Kansas was under water. The relatively deep sea advanced and retreated, leaving behind sandstones and shales of the Lower Cretaceous, such as the Dakota Formation, and the Upper Cretaceous limestones and chalk of the Greenhorn and Niobrara Chalk Formations. Much of the Dakota Formation consists of colorful clay shales, as well as beds of lignite that were used by early pioneers for heating (The Geologic History of Kansas)."